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Mercury in precipitation in Indiana, January 2004–December 2005

Mercury in precipitation was monitored during 2004–2005 at five locations in Indiana as part of the National Atmospheric Deposition Program–Mercury Deposition Network (NADP–MDN). Monitoring stations were operated at Roush Lake near Huntington, Clifty Falls State Park near Madison, Fort Harrison State Park near Indianapolis, Monroe County Regional Airport near Bloomington, and Indiana Dunes National Lakeshore near Porter. At these monitoring stations, precipitation amounts were measured continuously and weekly samples were collected for analysis of mercury by methods achieving detection limits as low as 0.05 ng/L (nanograms per liter). Wet deposition was computed as the product of mercury concentration and precipitation. The data were analyzed for seasonal patterns, temporal trends, and geographic differences. In the 2 years, 520 weekly samples were collected at the 5 monitoring stations and 448 of these samples had sufficient precipitation to compute mercury wet deposition. The 2-year mean mercury concentration at the five monitoring stations (normalized to the sample volume) was 10.6 ng/L. As a reference for comparison, the total mercury concentration in 41 percent of the samples analyzed was greater than the statewide Indiana water-quality standard for mercury (12 ng/L, protecting aquatic life) and 99 percent of the concentrations exceeded the most conservative Indiana water-quality criterion (1.3 ng/L, protecting wild mammals and birds). The normalized annual mercury concentration at Clifty Falls in 2004 was the fourth highest in the NADP–MDN in eastern North America that year. In 2005, the mercury concentrations at Clifty Falls and Indiana Dunes were the ninth highest in the NADP–MDN in eastern North America. At the five monitoring stations during the study period, the mean weekly total mercury deposition was 0.208 µg/m 2 (micrograms per square meter) and mean annual total mercury deposition was 10.8 µg/m 2 . The annual mercury deposition at Clifty Falls in 2004 and 2005 was in the top 25 percent of the NADP–MDN stations in eastern North America. Mercury concentrations and deposition varied at the five monitoring stations during 2004–2005. Mercury concentrations in wet-deposition samples ranged from 1.2 to 116.6 ng/L and weekly mercury deposition ranged from 0.002 to 1.74 µg/m 2 . Data from weekly samples exhibited seasonal patterns. During April through September, total mercury concentrations and deposition were higher than the median for all samples. Annual precipitation at four of the five monitoring stations was within 10 percent of normal both years, with the exception of Indiana Dunes, where precipitation was 23 percent below normal in 2005. Episodes of high mercury deposition, which were the top 10 percent of weekly mercury deposition at the five monitoring stations, contributed 39 percent of all mercury deposition during 2004–2005. Mercury deposition more than 1.04 µg/m 2 (5 times the mean weekly deposition) was recorded for 12 samples. These episodes of highest mercury deposition were recorded at all five monitoring stations, but the most (7 of 12) were at Clifty Falls and contributed 34.4 percent of the total deposition at that station during 2004–2005. Weekly samples with high mercury deposition may help to explain the differences in annual mercury deposition among the five monitoring stations in Indiana. A statistical evaluation of the monitoring data for 2001–2005 indicated several statistically significant temporal trends. A statewide (5-station) decrease (p = 0.007) in mercury deposition and a statewide decrease (p = 0.059) in mercury concentration were shown. Decreases in mercury deposition (p = 0.061 and p = 0.083) were observed at Roush Lake and Bloomington. A statistically significant trend was not observed for precipitation at the five monitoring stations during this 5-year period. A potential explanation for part of the statewide decrease in mercury concentration and mercury deposition was a 28 percent decrease in the total estimated annual mercury emissions in Indiana between 2002 and 2005. Mercury deposition statistically was correlated most closely to precipitation in the 448 samples, 2004–2005, and this relation was demonstrated by statewide maps of annual precipitation and annual mercury deposition based on precipitation data from 127 National Weather Service Cooperative Observer Program stations. However, one area in southeastern Indiana in the vicinity of Clifty Falls exhibited high mercury deposition that might be related more to mercury concentration than to precipitation. This is because areas with the same range of precipitation as southeastern Indiana were mapped with less mercury deposition. Other data demonstrate a geographic difference for mercury in precipitation in the vicinity of the Clifty Falls monitoring station. The weekly mercury concentrations at Clifty Falls were statistically higher than concentrations at Roush Lake, Fort Harrison, and Bloomington. Clifty Falls data ranked highest among the five monitoring stations for mercury concentration and mercury deposition, 2004–2005, and in the previous 3 years. Episodes of high mercury deposition were recorded most often at Clifty Falls in 2004–2005 and in the previous 3 years. Statistical trends in mercury concentration or mercury deposition were not observed for the Clifty Falls data. A potential explanation for this geographic difference is that annual mercury emissions from sources in the vicinity of Clifty Falls were higher than those at the other stations. Other factors may help explain the differences in total mercury concentrations, such as the types of mercury emissions, mercury transport from stationary sources outside Indiana, and meteorological conditions. Additional data are needed to assign a localized or regional boundary to the area affected by high deposition of mercury near Clifty Falls.

Indiana↗

Effects of wastewater effluent discharge and treatment facility upgrades on environmental and biological conditions of Indian Creek, Johnson County, Kansas, June 2004 through June 2013

Indian Creek is one of the most urban drainage basins in Johnson County, Kansas, and environmental and biological conditions of the creek are affected by contaminants from point and other urban sources. The Johnson County Douglas L. Smith Middle Basin (hereafter referred to as the “Middle Basin”) and Tomahawk Creek Wastewater Treatment Facilities (WWTFs) discharge to Indian Creek. In summer 2010, upgrades were completed to increase capacity and include biological nutrient removal at the Middle Basin facility. There have been no recent infrastructure changes at the Tomahawk Creek facility; however, during 2009, chemically enhanced primary treatment was added to the treatment process for better process settling before disinfection and discharge with the added effect of enhanced phosphorus removal. The U.S. Geological Survey, in cooperation with Johnson County Wastewater, assessed the effects of wastewater effluent on environmental and biological conditions of Indian Creek by comparing two upstream sites to four sites located downstream from the WWTFs using data collected during June 2004 through June 2013. Environmental conditions were evaluated using previously and newly collected discrete and continuous data and were compared with an assessment of biological community composition and ecosystem function along the upstream-downstream gradient. This study improves the understanding of the effects of wastewater effluent on stream-water and streambed sediment quality, biological community composition, and ecosystem function in urban areas. After the addition of biological nutrient removal to the Middle Basin WWTF in 2010, annual mean total nitrogen concentrations in effluent decreased by 46 percent, but still exceeded the National Pollutant Discharge Elimination System (NPDES) wastewater effluent permit concentration goal of 8.0 milligrams per liter (mg/L); however, the NPDES wastewater effluent permit total phosphorus concentration goal of 1.5 mg/L or less was achieved at the Middle Basin WWTF. At the Tomahawk Creek WWTF, after the addition of chemically enhanced primary treatment in 2009, effluent discharges also had total phosphorus concentrations below 1.5 mg/L. After the addition of biological nutrient removal, annual total nitrogen and phosphorus loads from the Middle Basin WWTF decreased by 42 and 54 percent, respectively, even though effluent volume increased by 11 percent. Annual total phosphorus loads from the Tomahawk Creek WWTF after the addition of chemically enhanced primary treatment decreased by 54 percent despite a 33-percent increase in effluent volume. Total nitrogen and phosphorus from the WWTFs contributed between 30 and nearly 100 percent to annual nutrient loads in Indian Creek depending on streamflow conditions. In-stream total nitrogen primarily came from wastewater effluent except during years with the highest streamflows. Most of the in-stream total phosphorus typically came from effluent during dry years and from other urban sources during wet years. During 2010 through 2013, annual mean discharge from the Middle Basin WWTF was about 75 percent of permitted design capacity. Annual nutrient loads likely will increase when the facility is operated at permitted design capacity; however, estimated maximum annual nutrient loads from the Middle Basin WWTF were 27 to 38 percent lower than before capacity upgrades and the addition of biological nutrient removal to treatment processes. Thus, the addition of biological nutrient removal to the Middle Basin wastewater treatment process should reduce overall nutrient loads from the facility even when the facility is operated at permitted design capacity. The effects of wastewater effluent on the water quality of Indian Creek were most evident during below-normal and normal streamflows (about 75 percent of the time) when wastewater effluent represented about 24 percent or more of total streamflow. Wastewater effluent had the most substantial effect on nutrient concentrations in Indian Creek. Total and inorganic nutrient concentrations at the downstream sites during below-normal and normal streamflows were 10 to 100 times higher than at the upstream sites, even after changes in treatment practices at the WWTFs. Median total phosphorus concentrations during below-normal and normal streamflows at a downstream site were 43 percent lower following improvements in wastewater treatment processes. Similar decreases in total nitrogen were not observed, likely because total nitrogen concentrations only decreased in Middle Basin effluent and wastewater contributed a higher percentage to streamflows when nutrient samples were collected during the after-upgrade period. The wastewater effluent discharges to Indian Creek caused changes in stream-water quality that may affect biological community structure and ecosystem processes, including higher concentrations of bioavailable nutrients (nitrate and orthophosphorus) and warmer water temperatures during winter months. Other urban sources of contaminants also caused changes in stream-water quality that may affect biological community structure and ecosystem processes, including higher turbidities downstream from construction areas and higher specific conductance and chloride concentrations during winter months. Chloride concentrations exceeded acute and chronic exposure criteria at all Indian Creek study sites, regardless of wastewater influence, for weeks or months during winter. Streambed sediment chemistry was affected by wastewater (elevated nutrient and organic wastewater-indicator compound concentrations) and other contaminants from urban sources (elevated polyaromatic hydrocarbon concentrations). Overall habitat conditions were suboptimal or marginal at all sites; general decline in habitat conditions along the upstream-downstream gradient likely was caused by the cumulative effects of urbanization with increasing drainage basin size. Wastewater effluent likely affected algal periphyton biomass and community composition, primary production, and community respiration in Indian Creek. Functional stream health, evaluated using a preliminary framework based on primary production and community respiration, was mildly or severely impaired at most downstream sites relative to an urban upstream Indian Creek site. The mechanistic cause of the changes in these biological variables are unclear, though elevated nutrient concentrations were positively correlated with algal biomass, primary production, and community respiration. Macroinvertebrate communities indicated impairment at all sites, and Kansas Department of Health and Environment aquatic life support scores indicated conditions nonsupporting of aquatic life, regardless of wastewater influences. Urban influences, other than wastewater effluent discharge, likely control macroinvertebrate community structure in Indian Creek. Changes in treatment processes at the Middle Basin and Tomahawk Creek WWTFs improved wastewater effluent quality and decreased nutrient loads, but wastewater effluent discharges still had negative effects on the environmental and biological conditions at downstream Indian Creek sites. Wastewater effluent discharge into Indian Creek likely contributed to changes in measures of ecosystem structure (streamflow, water and streambed-sediment chemistry, algal biomass, and algal periphyton community composition) and function (primary production and community respiration) along the upstream-downstream gradient. Wastewater effluent discharges maintained streamflows and increased nutrient concentrations, algal biomass, primary production, and community respiration at the downstream sites. Functional stream health was severely impaired downstream from the Middle Basin WWTF and mildly impaired downstream from the Tomahawk WWTF relative to the urban upstream site. As distance from the Middle Basin WWTF increased, nutrient concentrations, algal biomass, primary production, and community respiration decreased, and functional stream health was no longer impaired 9.5 kilometers downstream from the discharge relative to the urban upstream site. Therefore, although wastewater effluent caused persistent changes in environmental and biological conditions and functional stream health at sites located immediately downstream from WWTF effluent discharges, some recovery to conditions more similar to the urban upstream site occurred within a relatively short distance.

Kansas↗

Effects of flow modification on a cattail wetland at the mouth of Irondequoit Creek near Rochester, New York: Water levels, wetland biota, sediment, and water quality

An 11-year (1990-2001) study of the Ellison Park wetland, a 423-acre, predominantly cattail (Typha glauca) wetland at the mouth of Irondequoit Creek, was conducted to document the effects that flow modifications, including installation of a flow-control structure (FCS) in 1997 and increased diversion of stormflows to the backwater areas of the wetland, would have on the wetland's ability to decrease chemical loads transported by Irondequoit Creek into Irondequoit Bay on Lake Ontario. The FCS was designed to raise the water-surface elevation and thereby increase the dispersal and detention of stormflows in the upstream half of the wetland; this was expected to promote sedimentation and microbial utilization of nutrients, and thereby decrease the loads of certain constituents, primarily phosphorus, that would otherwise be carried into Irondequoit Bay. An ecological monitoring program was established to document changes in the wetland's water levels, biota, sedimentation rates, and chemical quality of water and sediment that might be attributable to the flow modifications. Water-level increases during storms were mostly confined to the wetland area, within about 5,000 ft upstream from the FCS. Backwater at a point of local concern, about 13,000 ft upstream, was due to local debris jams or constriction of flow by bridges and was not attributable to the FCS. Plant surveys documented species richness, concentrations of nutrients and metals in cattail tissues, and cattail productivity. Results indicated that observed differences among survey periods and between the areas upstream and downstream from the FCS were due to seasonal changes in water levels—either during the current year or at the end of the previous year's growing season—that reflected the water-surface elevation of Lake Ontario, rather than water-level control by the FCS. Results showed no adverse effects from the naturally high water levels that prevail annually during the spring and summer in the wetland, nor from the short-duration increases in water levels that result from FCS operation. Fish surveys documented the use of the wetland by 44 species, of which 25 to 29 species were found in any given year. Community composition was relatively consistent during the study, but seasonal and year-to-year variations in dominant resident and nonresident species were noted, and probably reflected natural or regional population patterns in Lake Ontario and Irondequoit Bay. The FCS allowed fish passage at all water levels and had no discernible adverse effect on the fish community. Bird surveys documented the use of the wetland by more than 90 species for breeding, feeding, and migration. Ground-nesting birds were unaffected by the FCS. Seasonally high water levels, rather than short-duration increases caused by the FCS, might have caused the scarcity or absence of certain wetland species by limiting the extent of breeding habitat for some species and the exposure of mud flats that attracted other species. Some noticeably scarce or absent species also were rare or absent elsewhere along the south-central shore of Lake Ontario. Benthic-macroinvertebrate studies were of minimal use for evaluating the effect of the FCS because no surveys were conducted after FCS installation. The precontrol results allowed assessment of the ecological quality of the wetland on the basis of biotic indices, and generally indicated moderately to severely impaired conditions. Differences between the macroinvertebrate communities in the southern part of the wetland and those in the northern part were attributed to habitat differences, such as substrate composition, water depth, and density of submerged aquatic vegetation. Sedimentation rates in the areas upstream and downstream from the FCS increased after the flow modifications, more in the area upstream from the FCS than in the downstream area. The concurrent downstream increase and the dynamic patterns of deposition and scour indicated that although the FCS and the other flow modifications undoubtedly were major factors in the postcontrol upstream increase in sedimentation rates, other factors, such as the magnitude, frequency, and the timing (season) of peak flows, might also have contributed. Periodic analyses of sediment samples from three longterm depositional sites in the wetland documented the concentrations of major and trace elements, polycyclic aromatic hydrocarbons, and organochlorine and organophosphate compounds. The concentrations of most constituents showed no substantial fluctuation or consistent upward or downward trend during the years sampled, nor did they identify any change after FCS installation. Comparison of the measured concentrations with sediment-quality guidelines that are used to assess the ecological quality of substrate environments indicated that the wetland was moderately to severely impaired—an assessment consistent with the benthic-macroinvertebrate biotic indices. During the precontrol period (1990–96), the wetland was a sink for particulate constituents (removal efficiencies for total phosphorus and total suspended solids were 28 and 47 percent, respectively), but had little effect on conservative constituents (chloride and sulfate). The wetland was a source of orthophosphate and ammonia (removal efficiencies were -38 and -84 percent, respectively). During the postcontrol period (1997–2001), the wetland continued to be a sink for particulate constituents (removal efficiencies for total phosphorus and total suspended solids were 45 and 52 percent, respectively); the exportation of orthophosphate by the wetland decreased (by 7 percent), whereas that of ammonia increased (by about 70 percent). The outflow loads of orthophosphate and ammonia represented about 15 and 2.3 percent of total phosphorus and total nitrogen loads, respectively. Changes in the loads of conservative constituents were negligible, and the overall removal efficiencies for other constituents during the precontrol period differed from those of the postcontrol period by no more than 5.4 percent. Statistical analyses of monthly inflow and outflow loads indicated significant differences between inflow and outflow loads of most constituents during the pre- and postcontrol periods. Load data were adjusted to remove the effects of dissimilar hydrologic conditions that prevailed during the pre- and postcontrol periods, and to isolate the water-quality-improvement effect that could be attributed solely to the FCS. Results indicated that the FCS contributed significantly to the decrease in total phosphorus loads, and slightly to a decrease in ammonia-plus-organic nitrogen loads, but had little or no significant effect on loads of other constituents.

New York↗

Sediment transport to and from small impoundments in northeast Kansas, March 2009 through September 2011

The U.S. Geological Survey, in cooperation with the Kansas Water Office, investigated sediment transport to and from three small impoundments (average surface area of 0.1 to 0.8 square miles) in northeast Kansas during March 2009 through September 2011. Streamgages and continuous turbidity sensors were operated upstream and downstream from Atchison County, Banner Creek, and Centralia Lakes to study the effect of varied watershed characteristics and agricultural practices on sediment transport in small watersheds in northeast Kansas. Atchison County Lake is located in a predominantly agricultural basin of row crops, with wide riparian buffers along streams, a substantial amount of tile drainage, and numerous small impoundments (less than 0.05 square miles; hereafter referred to as “ponds”). Banner Creek Lake is a predominantly grassland basin with numerous small ponds located in the watershed, and wide riparian buffers along streams. Centralia Lake is a predominantly agricultural basin of row crops with few ponds, few riparian buffers along streams, and minimal tile drainage. Upstream from Atchison County, Banner Creek, and Centralia Lakes 24, 38, and 32 percent, respectively, of the total load was transported during less than 0.1 percent (approximately 0.9 days) of the time. Despite less streamflow in 2011, larger sediment loads during that year indicate that not all storm events transport the same amount of sediment; larger, extreme storms during the spring may transport much larger sediment loads in small Kansas watersheds. Annual sediment yields were 360, 400, and 970 tons per square mile per year at Atchison County, Banner, and Centralia Lake watersheds, respectively, which were less than estimated yields for this area of Kansas (between 2,000 and 5,000 tons per square mile per year). Although Centralia and Atchison County Lakes had similar percentages of agricultural land use, mean annual sediment yields upstream from Centralia Lake were about 2.7 times those at Atchison County or Banner Creek Lakes. These data indicate larger yields of sediment from watersheds with row crops and those with fewer small ponds, and smaller yields in watersheds which are primarily grassland, or agricultural with substantial tile drainage and riparian buffers along streams. These results also indicated that a cultivated watershed can produce yields similar to those observed under the assumed reference (or natural) condition. Selected small ponds were studied in the Atchison County Lake watershed to characterize the role of small ponds in sediment trapping. Studied ponds trapped about 8 percent of the sediment upstream from the sediment-sampling site. When these results were extrapolated to the other ponds in the watershed, differences in the extent of these ponds was not the primary factor affecting differences in yields among the three watersheds. However, the selected small ponds were both 45 years old at the time of this study, and have reduced capacity because of being filled in with sediments. Additionally, trapping efficiency of these small ponds decreased over five observed storms, indicating that processes that suspended or resuspended sediments in these shallow ponds, such as wind and waves, affected their trapping efficiencies. While small ponds trapped sediments in small storms, they could be a source of sediment in larger or more closely spaced storm events. Channel slope was similar at all three watersheds, 0.40, 0.46, and 0.31 percent at Atchison County, Banner Creek, and Centralia Lake watersheds, respectively. Other factors, such as increased bank and stream erosion, differences in tile drainage, extent of grassland, or riparian buffers, could be the predominant factors affecting sediment yields from these basins. These results show that reference-like sediment yields may be observed in heavily agricultural watersheds through a combination of field-scale management activities and stream channel protection. When computing loads using published erosion rates obtained by single-point survey methodology, streambank contributions from the main stem of Banner Creek are three times more than the sediment load observed by this study at the sediment sampling site at Banner Creek, 2.6 times more than the sediment load observed by this study at the sediment sampling site at Clear Creek (upstream from Atchison County Lake), and are 22 percent of the load observed by this study at the sediment sampling site at Black Vermillion River above Centralia Lake. Comparisons of study sites to similarly sized urban and urbanizing watersheds in Johnson County, Kansas indicated that sediment yields from the Centralia Lake watershed were similar to those in construction-affected watersheds, while much smaller sediment yields in the Atchison County and Banner Creek watersheds were comparable to stable, heavily urbanized watersheds. Comparisons of study sites to larger watersheds upstream from Tuttle Creek Lake indicate the Black Vermillion River watershed continues to have high sediment yields despite 98 percent of sediment from the Centralia watershed (a headwater of the Black Vermillion River) being trapped in Centralia Lake. Estimated trapping efficiencies for the larger watershed lakes indicated that Banner Creek and Centralia Lakes trapped 98 percent of incoming sediment, whereas Atchison County Lake trapped 72 percent of incoming sediment during the 3-year study period.

Kansas↗

Development of a two-stage lifecycle model to inform the trap-and-haul program for Oncorhynchus kisutch (coho salmon) in the Lewis River, Washington

Restoration of salmon populations in the upper Lewis River Basin, Washington, depends on a trap-and-haul program owing to the Lewis River Hydroelectric Project (hereinafter referred to as “Project”) operated by PacifiCorp and Cowlitz Public Utilities District (hereinafter referred to as “Utilities”), which has been a barrier to salmon passage since the 1930s. Thus, sustaining the Oncorhynchus kisutch (Walbaum, 1792; coho salmon) population upstream from the Project currently depends on two fundamental factors: (1) the collection of upstream migrating adult coho salmon at Merwin Dam, the lowermost dam within the Project, and transporting them by truck to spawn above Swift Dam, the uppermost dam within the Project; and (2) the collection of out-migrating juvenile coho salmon at the downstream collection facility at Swift Dam for transport and release below the Project. The reintroduction program began once the downstream collection facility at Swift Dam was commissioned in late 2012, with the first year of transport data being collected in 2013. Over the past decade, the Utilities have been collecting data on juvenile outmigrants and adult fish returns at the dams. The need to construct a lifecycle model for Lewis River anadromous fish was identified by the Lewis River Aquatic Technical Subgroup, with the understanding that many years (more than 15 years) of data collection are needed to adequately measure the lifecycle production of salmon. The U.S. Geological Survey was contracted to develop and apply the model to past data at the Lewis River dams to help inform future data collection and provide a framework that can be updated annually to measure trap-and-haul program performance within a lifecycle context. Because coho salmon can live as long as 5 years, estimating demographic parameters for coho salmon populations over their lifecycle requires at least 10 or more years of data collection. Over the past decade, PacifiCorp has been collecting data on fish collection efficiency and the numbers of adult and juvenile salmon transported around the Lewis River dams, making this an ideal time to formulate a lifecycle model that can guide future data collection efforts and provide preliminary information to resource managers. The goal of the statistical lifecycle model is to estimate annual production and survival during two critical life-stage transitions: (1) the freshwater production from escapement of adults released upstream from Swift Dam, and the collection of downstream migrating juveniles at the downstream passage facility at Swift Dam; and (2) the smolt-to-adult survival from the time of collection at Swift Dam to their return as adults. We used the Beverton-Holt stock-recruitment model to estimate juvenile production from the number of spawners (Beverton and Holt, 1957). This approach allowed us to test for density dependence at current spawner abundances while estimating annual productivity, defined as the number of juveniles produced per spawner at low spawner abundance. Productivity was then expressed as a function of the number of juveniles collected and transported downstream from the Project. Because juvenile fish collection efficiency (FCE) directly affects the number of juveniles that survive to continue downstream migration, FCE is a primary determinant of fish production. Consequently, the modeling framework is well suited to evaluate the performance of trap-and-haul programs within a lifecycle context. The objectives of this study were to (1) gather and collate available data on adult and juvenile coho salmon at Merwin and Swift Dams; (2) quantify adult escapement, juvenile abundance, and the age at outmigration and adult return; (3) describe, formulate and fit the integrated population model to the data; and (4) summarize our findings, identify data gaps, and identify opportunities for future studies that could improve model estimation and inference. Our key findings were: (1) over and above the number of spawning females, FCE was the primary factor affecting productivity of coho salmon above Swift Dam; (2) smolt-to-adult return (SAR) rates were relatively high considering that harvest was included in the estimate, averaging about 4.5 percent and ranging as high as 12.9 percent; and (3) juvenile capacity upstream from Swift Dam was difficult to estimate due to the limited range in spawning females over the time series of data, suggesting the model may be improved by collecting data at higher spawner abundances. In addition, by including FCE in the model, we estimated that the median pre-collection productivity, defined as the number of juveniles produced per spawner when FCE=1, was 64 juveniles per spawner. Because the two-stage lifecycle model partitions factors that affect fish production in rivers versus the ocean, the model estimates may help inform fishery managers about the overall role that fish collection at Swift Dam plays in the recovery and sustainability of Lewis River coho salmon. By providing the model with (1) more years of data, (2) higher numbers of spawning females, and (3) data on age at juvenile migration in relation to age at adult return, greater certainty in the estimates of capacity and SAR can be attained. Ultimately, information provided by the model may assist in the evaluation and continued improvement of the current trap-and-haul program to support anadromous fishes in the Lewis River Basin.

Washington↗

Streams, springs, and volcanic lakes for volcano monitoring

Introduction Volcanic unrest can trigger appreciable change to surface waters such as streams, springs, and volcanic lakes. Magma degassing produces gases and soluble salts that are absorbed into groundwater that feeds streams and lakes. As magma ascends, the amount of heat and degassing will increase, and so will any related geochemical and thermal signal. Subsurface magma movement can cause pressurization that alters hydrostatic head and may induce groundwater discharge. Fluid-pressure changes have been linked to distal volcano-tectonic earthquakes (White and McCausland, 2016; Coulon and others, 2017) and phreatic eruptions (for example, Yamaoka and others, 2016). Clearly, changes in groundwater and surface waters are both indicators of unrest and clues to how and where magma is rising toward the surface. Where possible, it is prudent to incorporate real-time hydrologic data into multiparameter monitoring of restless volcanoes. Hydrologic dynamics can also be tracked by changes in groundwater levels that are commonly measured in shallow boreholes (see of Flinders, A.F., Lowenstern, J.B., Coombs, M.L., and Poland, M.P., eds., Recommended capabilities and instrumentation for volcano monitoring in the United States: U.S. Geological Survey Scientific Investigations Report 2024–5062–K, 5 p., https://doi.org/10.3133/sir20245062k. ">chapter K , this volume, on boreholes; Hurwitz and Lowenstern, 2024). Although inferred to be common, relatively few volcano-hydrology anomalies are well documented, and many are essentially anecdotal (Newhall and others, 2001), reflecting the fact that high-resolution time series remain rare. Extreme examples include the 2008 eruption of Nevado del Huila, Colombia, where relatively minor phreatomagmatic eruptions were accompanied by expulsion of as much as 300 million cubic meters of groundwater from fissures high on the volcano (Worni and others, 2011), generating large lahars. Substantial decreases in flow rate from springs about 8 kilometers from the summit of Mayon Volcano, Philippines, have been noted before most eruptions in the 20th century (Newhall and others, 2001). Stream monitoring at Redoubt Volcano in 2009 allowed Werner and others (2012) to recognize that groundwater was unable to absorb (or scrub) the high flux of volcanic gas and that a high CO 2 /SO 2 precursor signal had been evident for 5 months prior to the eruption. A key to better interpreting hydrologic anomalies—or even identifying them—is therefore obtaining adequate baseline data. Most hydrologic monitoring at U.S. volcanoes has been accomplished by intermittent sampling surveys with annual or less frequent sampling (for example, https://hotspringchem.wr.usgs.gov/index.php ). More frequent sampling, however, generally is needed to establish reliable baselines. A recent hydrologic and hydrothermal monitoring experiment at 25 sites and 10 of the 12 level 4 (very high threat) volcanoes in the U.S. portion of the Cascade Range demonstrated that there is sufficient temporal variability in hydrothermal fluxes, even during quiescent periods, that one-time measurements will commonly have limited interpretive value (Crankshaw and others, 2018). Thus, surveys are best augmented with data from streamgages (for example, Evans and others, 2004; Bergfeld and others, 2008). Streamflow (water discharge) data allow measured temperature and specific conductance to be converted to heat and solute mass fluxes, which could be insightful parameters for detecting anomalous activity (McCleskey and others, 2012). At the Yellowstone Caldera, long-term monitoring of river solutes has allowed calculation of the chloride flux, a proxy for heat discharge (Hurwitz and others, 2007; McCleskey and others, 2016) from the subsurface magma. This is readily accomplished because data from streamgages are continuously recorded and archived by the U.S. Geological Survey (USGS) National Water Information System (NWIS) (USGS, 2024). Similar studies on stratovolcanoes or shield volcanoes would be scientifically useful, and yet are logistically challenging, requiring streamgages on numerous radial drainages complemented by either frequent manual sampling or numerous deployments of equipment to measure water temperature and specific conductance as a proxy for water chemistry. Another challenge is that some volcanic areas, especially shield volcanoes, are characterized by near-surface porous rocks and soils, such that surface streams are rare and replaced by distant, dilute large-volume springs with only a trace of any original volcanically sourced water (Manga, 2001; Hurwitz and others, 2021). Volcanic lakes are worthy of special attention for monitoring efforts, as their temperature and composition can provide evidence of increased flux of volatile-rich fluids from below. Quantifying changes in volatile and heat release from magma can be simpler in lakes than for volcanoes with radial drainages and no major lakes. Moreover, volcanic lakes pose a range of hazards themselves, including phreatomagmatic eruptions, debris flows, flank collapse, tsunamis, and toxic gas release (Mastin and Witter, 2000; Delmelle and others, 2015; Manville, 2015; Rouwet and others, 2015)—hazards that have historically been responsible for substantial loss of life at many volcanoes worldwide (Manville, 2015). Catastrophic CO 2 release at Lake Nyos, Cameroon, in 1986 suffocated about 1,750 people and about 3,500 livestock and was probably triggered by a large landslide into the gas-saturated lake (Kling and others, 1987; Evans and others, 1993). Gas-charged springs in Soda Bay within Clear Lake (California) have caused almost a dozen deaths to bathers in the past hundred years (ABC News, 2000). A 2005 example of lake overturn and abundant gas release was documented at Mount Chiginagak in Alaska (Schaefer and others, 2008) but did not result in any human casualties. Although thermally stratified lakes, which promote trapping of exsolved magmatic gas, tend to develop in tropical regions, the phenomenon can also arise where salinity creates meromixis (a condition in which a lake does not mix completely), as occurs in Mono Lake, California (Jellison and Melack, 1993; Jellison and others, 1998). If magma erupts or flows into a lake, the interaction between hot magma and cold water can be explosive (Mastin and others, 2004; Zimanowski and others, 2015) and substantially expand the area affected by the eruption. Another hazard is the breaching of crater rims by landslides triggered by volcanic and (or) seismic activity. Under some circumstances, substantial volumes of water can be displaced, leading to large floods and lahars. Late Holocene lake flooding from Aniakchak Crater in the Alaska Peninsula (Waythomas, 2022) and from Paulina Lake in Newberry Crater, Oregon (Chitwood and Jensen, 2000), caused by the failure of outlet sills, testify to the substantial hazards at lake-filled calderas. Several volcanic systems in the United States host lakes known to receive heat and gas from underlying magma. These lakes vary widely in area, depth, and chemical composition. Lakes are present at level 4 volcanoes, including Crater Lake and Newberry Volcano in Oregon; Yellowstone Caldera in Wyoming; Long Valley Caldera, Clear Lake volcanic field, Medicine Lake, and Salton Buttes in California; and Aniakchak Crater, Mount Katmai, Fisher Caldera, Mount Okmok, and Kaguyak Crater, among others, in Alaska. A water lake was present in Halemaʻumaʻu, the crater of Kīlauea, Hawai‘i (fig. F1), from October 2019 to December 2020. Level 3 volcanoes with lakes include Mono Lake volcanic field (Calif.), Mount Bachelor (Ore.), Ukinrek Maars and Mount Chiginagak (Alaska), and Soda Lake (Nevada). In addition, there are lakes at many levels 1 and 2 volcanoes. In the United States, there are no strongly acidic lakes that receive abundant input of magmatic gas, such as those found at Mount Ruapehu (New Zealand), Ijen and Kelud (Indonesia), and Poás (Costa Rica). Nevertheless, many contain fluids that provide clues to magmatic processes below. Since publication of a previous report on recommended instrumentation for volcano monitoring (Moran and others, 2008), continuous hydrologic monitoring has become increasingly feasible. However, changes in water pressure, temperature, and chemistry remain, in general, poorly studied phenomena at volcanoes (Sparks, 2003; National Academies of Sciences, Engineering, and Medicine, 2017). Recent efforts by the USGS have included the temporary study of Cascade Range volcanoes, which included frequent (15 minute to hourly) temporal sampling of temperature, depth, and conductivity (Crankshaw and others, 2018; Ingebritsen and Evans, 2019). At Yellowstone Caldera, many streamgages have now added thermistors and specific conductance sensors, allowing estimation of time-dependent chloride flux as a proxy for variations in subsurface heat flux (McCleskey and others, 2012, 2016). Efforts to better understand lakes have also accelerated, with bathymetric mapping and sampling carried out at several locations in the United States. Especially thorough work was done at Yellowstone Lake thanks to the Hydrothermal Dynamics of Yellowstone Lake (HD-YLAKE, https://hdylake.org ) project, funded primarily by the National Science Foundation. In addition to geophysical surveys and recovery of cores and other samples, HD-YLAKE investigations included remotely operated vehicle (ROV) investigations of hydrothermal vents on the lake floor (fig. F2). Data collected by the ROV provided a better understanding of the thermal and chemical influx from lake-bottom hydrothermal systems (Sohn and others, 2017). In this chapter, we focus on detecting changes in the chemistry, temperature, discharge, or water levels of streams, springs, and lakes that can be caused by seismicity, volumetric strains, or increases in gas flux associated with ascending magma. There is unavoidable overlap with other chapters of this report. Samples of water and gas can also be obtained in boreholes ( of Flinders, A.F., Lowenstern, J.B., Coombs, M.L., and Poland, M.P., eds., Recommended capabilities and instrumentation for volcano monitoring in the United States: U.S. Geological Survey Scientific Investigations Report 2024–5062–K, 5 p., https://doi.org/10.3133/sir20245062k. ">chapter K , this volume; Hurwitz and Lowenstern, 2024), both shallow and deep. Gas monitoring ( of Flinders, A.F., Lowenstern, J.B., Coombs, M.L., and Poland, M.P., eds., Recommended capabilities and instrumentation for volcano monitoring in the United States: U.S. Geological Survey Scientific Investigations Report 2024–5062–E, 11 p., https://doi.org/10.3133/sir20245062e.">chapter E , this volume; Lewicki and others, 2024) relies in part on samples from springs and wells, particularly where measurable gas plumes are absent. Water acts as a trigger and lubricant for landslides and sediment-rich floods, and so hydrology has obvious relevance for lahar monitoring, as discussed in of Flinders, A.F., Lowenstern, J.B., Coombs, M.L., and Poland, M.P., eds., Recommended capabilities and instrumentation for volcano monitoring in the United States: U.S. Geological Survey Scientific Investigations Report 2024–5062–H, 6 p., https://doi.org/10.3133/sir20245062h. ">chapter H (this volume; Thelen and others, 2024). Shared situational awareness among scientists engaged in geophysical, gas, and hydrologic monitoring will improve overall understanding of the volcanic hazard.

Scientific Investigations Report↗

U.S. Geological Survey Earthquake Hazards Program decadal science strategy, 2024–33

Executive Summary Earthquakes represent one of our Nation’s most significant and costly natural hazards, with estimated annual loses from earthquakes close to $15 billion in 2023. Over the past two centuries, 37 U.S. States have experienced an earthquake exceeding a magnitude of 5, and 50 percent of States have a significant potential for future damaging shaking; these statistics speak to the need for nationwide interest and investment in earthquake hazard characterization and risk reduction. Authorized under the Earthquake Hazards Reduction Authorization Act, the U.S. Geological Survey (USGS) Earthquake Hazards Program (EHP) provides the scientific information, situational awareness, and knowledge necessary to reduce deaths, injuries, and economic losses from earthquakes and earthquake-induced tsunamis, landslides, and soil liquefaction. The EHP supports activities in three focused topical areas: (1) earthquake monitoring, (2) hazard assessment, and (3) applied research, using the results of each—and the coordination among them—to further support risk translation and communication in regions at risk nationwide. For earthquake monitoring, the Advanced National Seismic System (ANSS), a cooperative effort of USGS networks, university partner regional seismic networks, and real-time geodetic networks, collects and analyzes data on earthquakes; issues timely, reliable notifications of their occurrence and impacts; and provides data for earthquake research, hazard, and risk assessment as a foundation for building an earthquake-resilient Nation. The USGS-operated ShakeAlert Earthquake Early Warning system is a recent addition to EHP’s ANSS infrastructure. In the realm of earthquake hazard assessment, the EHP contributes to earthquake risk mitigation strategies by developing the National Seismic Hazard Model and maps, and other related products, that describe the likelihood and potential effects of earthquakes nationwide, especially in the urban areas of highest risk. The EHP also conducts research on the causes, characteristics, and effects of earthquakes and prioritizes work that directly increases the accuracy and precision of earthquake hazards assessments, earthquake forecasts, and earthquake monitoring and situational-awareness products and that supports the Nation’s earthquake mitigation practices. Bridging the EHP’s efforts across research, hazard assessments, and earthquake monitoring is a broad and comprehensive collection of earthquake information products, including the National Seismic Hazard Model, ShakeAlert, and other products describing impact, such as ShakeMap and PAGER (Prompt Assessment of Global Earthquakes for Response), which have been developed and integrated into EHP’s real-time monitoring systems. EHP funds external partners to carry out many important collaborative activities through an active external grants program—one of the largest in the USGS—and through cooperative agreements with other partners such as the university-operated regional seismic networks, funded as part of the ANSS. To continue its support of earthquake hazard characterization and risk reduction, the EHP aims to strengthen its foundational products and practices while positioning itself to respond to the evolving needs of the Nation and follow best practices of the scientific community. This document describes a strategy for the program to ensure it can meet these demands. The foundational priorities outlined in this strategy represent those activities that remain critical to the core functionality of the program and those that can be supported under current fiscal year 2024-level appropriations. Priorities described as aspirational are important for future growth, and to maintain the program’s position as a leading global resource in earthquake science, but would require increases in appropriated funding to be fully realized. Across the program’s portfolio of activities, several major themes have been identified as the most critical activities to advance EHP science over the coming decade. Together, these activities provide the framework necessary to integrate critical hazard characterization and risk reduction activities across the program. They provide the structure for research to advance the understanding of where, when, and why earthquakes occur and how we can use improved knowledge to drive short-term and actionable forecasts of seismic activity. They expand the usefulness of critical earthquake products and advance the sophistication of those products to keep pace with the rapidly evolving needs of an ever-expanding user base while maintaining the position of the USGS as a global leader in earthquake science. Focus on system-level science. Establish an automated earthquake-processing pipeline. Enhance the accuracy and reliability of the ShakeAlert Earthquake Early Warning system and plan for extension to other regions. Implement time-dependent earthquake forecasting. Develop physically realistic models. Expand computational capacity. This science strategy is organized into three primary sections. The first section provides an overview of the EHP and its budget, governance, and program council. Readers familiar with the program may wish to focus on the second section, which describes the core of the science strategy, including priorities across each of the EHP’s major program activities in monitoring, hazard assessment, and targeted research. The third section outlines science priorities that cut across program activities, including those involving collaborations external to the EHP.

American Samoa, Guam, Northern Marianas Islands, U↗

Contributing recharge areas, groundwater travel time, and groundwater quality of the Missouri River alluvial aquifer near the Independence, Missouri, well field, 1997-2008

The City of Independence, Missouri, operates a well field in the Missouri River alluvial aquifer. Contributing recharge areas (CRA) were last determined for the well field in 1996. Since that time, eight supply wells have been installed in the area north of the Missouri River and well pumpage has changed for the older supply wells. The change in pumping has altered groundwater flow and substantially changed the character of the CRA and groundwater travel times to the supply wells. The U.S Geological Survey, in a cooperative study with the City of Independence, Missouri, simulated steady-state groundwater flow for 2007 well pumpage, average annual river stage, and average annual recharge. Particle-tracking analysis was used to determine the CRA for supply wells and monitoring wells, and the travel time from recharge areas to supply wells, recharge areas to monitoring wells, and monitoring wells to supply wells. The simulated CRA for the well field is elongated in the upstream direction and extends to both sides of the Missouri River. Groundwater flow paths and recharge areas estimated for monitoring wells indicate the origin of water to each monitoring well, the travel time of that water from the recharge area, the flow path from the vicinity of each monitoring well to a supply well, and the travel time from the monitoring well to the supply well. Monitoring wells 14a and 14b have the shortest groundwater travel time from their contributing recharge area of 0.30 years and monitoring well 29a has the longest maximum groundwater travel time from its contributing recharge area of 1,701 years. Monitoring well 22a has the shortest groundwater travel time of 0.5 day to supply well 44 and monitoring well 3b has the longest maximum travel time of 31.91 years to supply well 10. Water-quality samples from the Independence groundwater monitoring well network were collected from 1997 to 2008 by USGS personnel during ongoing annual sampling within the 10-year contributing recharge area (CRA) of the Independence well field. Statistical summaries and the spatial and temporal variability of water quality in the Missouri River alluvial aquifer near the Independence well field were characterized from analyses of 598 water samples. Water-quality constituent groups include dissolved oxygen and physical properties, nutrients, major ions and trace elements, wastewater indicator compounds, fuel compounds, and total benzene, toluene, ethylbenzene, and xylene (BTEX), alachlor, and atrazine. The Missouri Secondary Maximum Contaminant Level (SMCL) for iron was exceeded in almost all monitoring wells. The Missouri Maximum Contaminant Level (MCL) for arsenic was exceeded 32 times in samples from monitoring wells. The MCL for barium was exceeded five times in samples from one monitoring well. The SMCL for manganese was exceeded 160 times in samples from all monitoring wells and the combined well-field sample. The most frequently detected wastewater indicator compounds were N,N-diethyl-meta-toluamide (DEET), phenol, caffeine, and metolachlor. The most frequently detected fuel compounds were toluene and benzene. Alachlor was detected in 22 samples and atrazine was detected in 37 samples and the combined well-field sample. The MCL for atrazine was exceeded in one sample from one monitoring well. Samples from monitoring wells with median concentrations of total inorganic nitrogen larger than 1 milligram per liter (mg/L) are located near agricultural land and may indicate that agricultural land practices are the source of nitrogen to groundwater. Largest median values of specific conductance; total inorganic nitrogen; dissolved calcium, magnesium, sodium, iron, arsenic, manganese, bicarbonate, and sulfate and detections of wastewater indicator compounds generally were in water samples from monitoring wells with CRAs that intersect the south bank of the Missouri River. Zones of higher specific conductance were located just upstream from the Independence well field at south-bank outfalls from wastewater treatment plants, the Blue River, and the south bank of the Missouri River near the closed oil refinery. The long-term presence of these south-bank outfalls and the large specific conductance indicate that the surface water at the south bank of the Missouri River near the Independence well field may have consistently higher dissolved solids and nutrients that can be induced into the aquifer by pumping. Large median concentrations of sodium and chloride from samples from monitoring wells may be the result of road salt use on State Highway 291 or from Mill Creek, which drains the uplands south of the Independence well field. Large median concentrations of arsenic in samples from some monitoring well nests are most likely associated with dissolution of iron and sulfide minerals and fluctuation between oxidizing and reducing conditions. Largest median concentrations for arsenic are in the shallow depth interval where fluctuations between oxidizing and reducing conditions occur. Median concentrations of iron are large in all monitoring wells and are most likely caused by the interaction between fluctuating oxidizing and reducing conditions and siderite and ferric hydroxide. Spatial and temporal trends are not evident from the fuel compounds or total BTEX sample results. Alachlor and atrazine were detected in most monitoring wells and atrazine was detected more often than alachlor. The source of alachlor and atrazine in groundwater near the Independence well field is most likely from nearby agricultural land management practices and (or) the Missouri River. Many of the samples from monitoring wells with alachlor or atrazine detections greater than 10 percent have contributing recharge areas that intersect either agricultural land or the Missouri River bed.

Missouri↗

Monitoring breeding and migration of neotropical migratory birds at Point Loma, San Diego County, California, 5-year summary, 2011–15

Executive Summary We operated a bird banding station on the Point Loma peninsula in western San Diego County, California, during spring and summer from 2011 to 2015. The station was established in 2010 as part of a long-term monitoring program for neotropical migratory birds during spring migration and for breeding birds as part of the Monitoring Avian Productivity and Survivorship (MAPS) program. During spring migration (April and May), 2011–15, we captured 1,760 individual birds of 54 species, 91 percent (1,595) of which were newly banded, fewer than 1 percent (3) of which were recaptures that were banded in previous years, and 9 percent (143 hummingbirds, 2 hawks, and 17 other birds) of which we released unbanded. We observed an additional 22 species that were not captured. Thirty-four individuals were captured more than once. Bird capture rate averaged 0.49 ± 0.07 captures per net-hour (range 0.41–0.56). Species richness per day averaged 6.87 ± 0.33. Cardellina pusilla (Wilson’s warbler) was the most abundant spring migrant captured, followed by Empidonax difficilis (Pacific-slope flycatcher), Vireo gilvus (warbling vireo), Zonotrichia leucophrys (white-crowned sparrow), and Selasphorus rufus (rufous hummingbird). Captures of white-crowned sparrow decreased, and captures of Pacific-slope flycatcher increased, over the 5 years of our study. Fifty-six percent of known-sex individuals were male and 44 percent were female. The peak number of new species arriving per day ranged from April 1 (2013-six species) to April 16 (2012-five species). A significant correlation was determined between the number of migrants captured each day per net-hour and the density of echoes on the Next-Generation Radar (NEXRAD) images across all 5 years, and in each year except 2014. NEXRAD radar imagery appears to be a useful tool for detecting pulses in migration. Our results indicate that Point Loma provides stopover habitat during migration for 76 migratory species, including 20 species of conservation concern. Two of these species, Vireo bellii pusillus (least Bell’s vireo) and Empidonax traillii (willow flycatcher) are listed as State and (or) federally threatened or endangered. Except for Archilochus alexandri (black-chinned hummingbird) and Setophaga occidentalis (hermit warbler), which arrived later during the migratory season in latter years of our study, median arrival dates for migratory species tended to be earlier each year or did not change across 5 years. Of the five most common migratory species, white-crowned sparrow and rufous hummingbird arrived earlier in latter years of the study, but Pacific-slope flycatcher, warbling vireo, and Wilson’s warbler median arrival dates were variable and showed no trend. We captured 1,680 individuals of 66 species during the MAPS/breeding season (May through August) across the 5 years of our study, 72 percent (1,211) of which were newly banded, 10 percent (167) of which were recaptures, and 18 percent (302 hummingbirds and other birds that escaped prior to banding) of which we released unbanded. Bird capture rate averaged 0.65 ± 0.21 captures per net-hour (range 0.12–2.54). Species richness per day ranged from 9.80 ± 5.01 to 14.20 ± 4.57. Calypte anna (Anna’s hummingbird) was the most abundant breeding species captured, followed by Oreothlypis celata (orange-crowned warbler), Psaltriparus minimus (bushtit), Pipilo maculatus (spotted towhee), Thryomanes bewickii (Bewick’s wren), Melozone crissalis (California towhee), and Chamaea fasciata (wrentit). Fifty-one percent of known-sex captures were female, and 49 percent were male. Thirty-one percent of known-age captures were juveniles. Populations of bushtits and orange-crowned warbler decreased significantly over 5 years. Anna’s hummingbird abundance was high for 4 years, and then decreased in 2015. Bewick’s wren and wrentit populations were highest in 2015. There was no obvious pattern in spotted towhee and California towhee abundance across 5 years. Annual breeding productivity for most species was low in 2014 and high in 2015. Bewick’s wren had the highest breeding productivity of the six most commonly captured species, followed by bushtit. Orange-crowned warbler had the lowest breeding productivity. Breeding productivity was a significant predictor of population size the next year for bushtit, but not for any other resident breeding species examined. Adult survivorship was generally high from 2013 to 14, and low from 2014 to 15. Wrentits had the highest survivorship of the most common species captured, followed by California towhee and orange-crowned warbler. Adult survivorship was lowest for bushtits and spotted towhees. Adult survivorship was a significant predictor of population size for bushtits, but not for any other resident species examined. Our monitoring results indicate that Point Loma provides breeding habitat for seven species of conservation concern. One of these species, the federally threatened Polioptila californica californica (California gnatcatcher), was documented breeding at the study site.

California↗

Groundwater-flow and land-subsidence model of Antelope Valley, California

Antelope Valley, California, is a topographically closed basin in the western part of the Mojave Desert, about 50 miles northeast of Los Angeles. The Antelope Valley groundwater basin is about 940 square miles and is separated from the northern part of Antelope Valley by faults and low-lying hills. Prior to 1972, groundwater provided more than 90 percent of the total water supply in the valley; since 1972, it has provided between 50 and 90 percent. Most groundwater pumping in the valley occurs in the Antelope Valley groundwater basin, which includes the rapidly growing cities of Lancaster and Palmdale. Groundwater-level declines of more than 270 feet in some parts of the groundwater basin have resulted in an increase in pumping lifts, reduced well efficiency, and land subsidence of more than 6 feet in some areas. Future urban growth and limits on the supply of imported water may increase reliance on groundwater. In 2011, the Los Angeles County Superior Court of California ruled that the Antelope Valley groundwater basin is in overdraft—groundwater extractions are in excess of the Court-defined safe yield of the groundwater basin. The Court determined that the safe yield of the adjudicated area of the basin was 110,000 acre-feet per year (acre-ft/yr). Natural recharge is an important component of total groundwater recharge in Antelope Valley; however, the exact quantity and distribution of natural recharge, primarily in the form of mountain-front recharge, is uncertain, with total estimates ranging from 30,000 to 160,000 acre-ft/yr. Technical experts, retained by parties to the adjudication, used 60,000 acre-ft/yr to estimate the sustainable yield of the basin, and this value was used in this study. In order to better understand the uncertainty associated with natural recharge and to provide a tool to aid in groundwater management, a numerical model of groundwater flow and land subsidence in the Antelope Valley groundwater basin was developed using old and new geohydrologic information. The groundwater-flow system consists of three aquifers: the upper, middle, and lower aquifers. The three aquifers, which were identified on the basis of the hydrologic properties, age, and depth of the unconsolidated deposits, consist of gravel, sand, silt, and clay alluvial deposits and clay and silty clay lacustrine deposits. Prior to groundwater development in the valley, recharge was primarily the infiltration of runoff from the surrounding mountains. Groundwater flowed from the recharge areas to discharge areas around the playas where it discharged from the aquifer system as either evapotranspiration or from springs. Partial barriers to horizontal groundwater flow, such as faults, have been identified in the groundwater basin. Water-level declines owing to groundwater development have eliminated the natural sources of discharge, and pumping for agricultural and urban uses have become the primary source of discharge from the groundwater system. Infiltration of return flow from agricultural irrigation has become an important source of recharge to the aquifer system. The groundwater-flow model of the basin was discretized horizontally into a grid of 130 rows and 118 columns of square cells 1 kilometer (0.621 mile) on a side, and vertically into four layers representing the upper (two layers), middle (one layer), and lower (one layer) aquifers. Faults that were thought to act as horizontal-flow barriers were simulated in the model. The model was calibrated to simulate steady-state conditions, represented by 1915 water levels and transient-state conditions during 1915–95, by using water-level and subsidence data. Initial estimates of the aquifer-system properties and stresses were obtained from a previously published numerical model of the Antelope Valley groundwater basin; estimates also were obtained from recently collected hydrologic data and from results of simulations of groundwater-flow and land-subsidence models of the Edwards Air Force Base area. Some of these initial estimates were modified during model calibration. Groundwater pumpage for agriculture was estimated on the basis of irrigated crop acreage and crop consumptive-use data. Pumpage for public supply, which is metered, was compiled and entered into a database used for this study. Estimated annual agricultural pumpage peaked at 395,000 acre-feet (acre-ft) in 1951 and then declined because of declining agricultural production. Recharge from irrigation return flows was assumed to be 30 percent of agricultural pumpage; delays associated with return flow moving through the unsaturated zone were also simulated. The annual quantity of mountain-front recharge initially was based on estimates from previous studies. The model was calibrated using the PEST software suite; prior information from the area was incorporated through the use of Tikhonov regularization. During model calibration, the estimated mountain-front recharge was reduced from the previous estimate of 30,300 acre-ft/yr to 29,150 acre-ft/yr. Results of the simulations using the calibrated model indicate that simulated groundwater pumpage exceeded recharge in most years, resulting in an estimated cumulative depletion in groundwater storage of 8,700,000 acre-ft during the transient-simulation period (1915–2005). About 15,000,000 acre-ft of cumulative groundwater pumpage was simulated during the transient-simulation period (1915–2005), reaching a maximum rate of about 400,000 acre-ft/yr in 1951. Groundwater pumpage resulted in simulated hydraulic heads declining by more than 150 feet (ft) compared to 1915 conditions in agricultural areas. The decline in hydraulic head in the groundwater basin is the result of this depletion of groundwater storage. In turn, the simulated decline in hydraulic head in the groundwater basin has resulted in the decrease in natural discharge from the basin and has caused compaction of aquitards, resulting in land subsidence. The areal distribution of total simulated land subsidence for 2005, after about 90 years of groundwater development, indicates that land subsidence occurred throughout almost the entire Lancaster subbasin, with a maximum of about 9.4 ft in the central and eastern parts of the subbasin. An important objective of this study was to systematically address the uncertainty in estimates of natural recharge and related aquifer parameters by using the groundwater-flow and land-subsidence model with observational data and expert knowledge. After the model was calibrated to the observations and a reasonable parameter set obtained, the parameter null space—parameter values that do not appreciably affect the model calibration but may have importance for prediction—was identified. The effect of parameter uncertainty on the estimation of mountain-front recharge was addressed using the Null-Space Monte Carlo method. The Pareto trade-off method of visualizing uncertainty was also used to portray the reasonableness of larger natural-recharge rates. Results indicate that the total mountain-front recharge likely ranges between 28,000 and 44,000 acre-ft/yr, which is appreciably less than published estimates of 60,000 acre-ft/yr. Additionally, expected errors associated with agricultural pumpage estimates used in this study were found to have relatively little effect on the estimates of mountain-front recharge, reflecting the difficulty in increasing recharge through manipulation of other components of the water budget. The calibrated model was used to simulate the response of the aquifer to potential future pumping scenarios: (1) no change in the distribution of pumpage, or status quo; (2) redistribution of pumpage; and (3) artificial recharge. All three of these scenarios specify a total pumpage throughout the Antelope Valley of 110,000 acre-ft/yr according to the safe yield value ruled by the Los Angeles County Superior Court of California. This reduction in groundwater pumpage is assumed uniform throughout the basin, based on a 10-percent reduction of the total pumpage in 2005 to achieve the 110,000 acre-ft/yr level. The calibrated Antelope Valley groundwater-flow and land-subsidence model was used to simulate the hydrologic effects of the three groundwater-management scenarios during a 50-year period by using the reduced, temporally constant, pumpage distribution. Results from the first scenario indicated that the total drawdown observed since predevelopment would continue, with values exceeding 325 ft near Palmdale; consequently, land subsidence would also continue, with additional subsidence (since 2005) exceeding 3 ft in the central part of the Lancaster subbasin. The second scenario evaluated redistributing pumpage from areas in the Lancaster subbasin where simulated hydraulic-head declines were the greatest to areas where declines were smallest. Neither a formal optimization algorithm nor water-rights allocations were considered when redistributing the pumpage. Results indicated that hydraulic heads near Palmdale, where the pumpage was reduced, would recover by about 200 ft compared to 2005 conditions, with only 30 ft of additional drawdown in the northwestern part of the Lancaster subbasin, where the pumpage was increased. The magnitude of the simulated additional land subsidence decreased slightly compared to the first, status quo, scenario but land subsidence continued to be simulated throughout most of the northern part of the Lancaster subbasin. The third scenario consisted of two artificial-recharge simulations along the Upper Amargosa Creek channel and at a site located north of Antelope Buttes. Results indicate that applying artificial recharge at these sites would yield continued drawdowns and associated land subsidence. However, the magnitudes of drawdown and subsidence would be smaller than those simulated in the status quo scenario, indicating that artificial-recharge operations in the Antelope Valley could be expected to reduce the magnitude and extent of continued water-level declines and associated land subsidence.

California↗

Evaluation of the behavior and movement patterns of adult coho salmon and steelhead in the North Fork Toutle River, Washington, 2005-2009

The 1980 eruption of Mount St. Helens severely affected the North Fork Toutle River (hereafter Toutle River), Washington, and threatened anadromous salmon (Oncorhynchus spp.) populations in the basin. The Toutle River was further affected in 1989 when a sediment retention structure (SRS) was constructed to trap sediments in the upper basin. The SRS completely blocked upstream volitional passage, so a fish collection facility (FCF) was constructed to trap adult coho salmon (O. kisutch) and steelhead (O. mykiss) so they could be transported upstream of the SRS. The Washington Department of Fish and Wildlife (WDFW) has operated a trap-and-haul program since 1989 to transport coho salmon and steelhead into tributaries of the Toutle River, upstream of the SRS. Although this program has allowed wild coho salmon and steelhead populations to persist in the Toutle River basin, the trap-andhaul program has faced many challenges that may be limiting the effectiveness of the program. We conducted a multi-year evaluation during 2005–2009 to monitor tagged fish in the upper Toutle River to provide information on the movements and behavior of adult coho salmon and steelhead, and to evaluate the efficacy of the FCF. Radio-tagged coho salmon and steelhead were released: (1) in Toutle River tributaries to evaluate the behavior and movements of fish released as part of the trap-and-haul program; (2) between the FCF and SRS to determine if volitional upstream passage through the SRS spillway was possible; (3) in the sediment plain upstream of the SRS to determine if volitional passage through the sediment plain was possible; and (4) downstream of the FCF to evaluate the efficacy of the structure. We also deployed an acoustic camera in the FCF to monitor fish movements near the entrance to the FCF, and in the fish holding vault where coho salmon and steelhead are trapped. A total of 20 radio-tagged coho salmon and 10 radio-tagged steelhead were released into Alder and Hoffstadt Creeks, the locations where trap-and-haul fish were released during 2005–2006. None of the tagged fish left the tributaries where they were released, but four radio tags were detected near the release sites, and it was not possible to determine if this was because the transmitters were regurgitated, or if some of the tagged fish had died. The results from this portion of the study indicated that trap-and-haul fish remain in the tributaries where they can spawn, but the trap-and-haul process is labor-intensive, and handling stress and mortality could occur. Tagged-fish releases upstream of the FCF showed that the SRS spillway was a complete migration barrier for all coho salmon and most steelhead. We released a total of 20 radio-tagged coho salmon and 23 radio-tagged steelhead during 2005–2007. No tagged coho salmon passed upstream through the SRS spillway, whereas 13 percent of the radio-tagged steelhead did migrate upstream through the structure. Radio-tagged coho salmon and steelhead that did not pass upstream remained in the FCF–SRS reach for an average of 7.5 and 16.1 d, respectively, before moving downstream. These data show that trap-and-haul releases of fish immediately upstream of the FCF would not be beneficial to coho salmon and steelhead populations in the system. Releasing tagged fish into the sediment plain was only moderately successful for coho salmon, but a large percentage of tagged steelhead moved upstream through the sediment plain to areas where spawning could presumably occur. During 2005–2009, we released 47 tagged coho salmon and 65 tagged steelhead into the sediment plain. Only 28 percent of the coho salmon were later detected upstream of the sediment plain, and the highest percentage of the release group (62 percent) never left the sediment plain. However, 69 percent of the steelhead moved upstream through the sediment plain and entered Toutle River tributaries or remained in the mainstem Toutle River where spawning could presumably occur. Adult steelhead can survive freshwater spawning, outmigrate to the ocean, and then return to spawn in successive years; 12 percent of the tagged steelhead successfully moved downstream of the FCF after the spawning period, and 5 percent of the tagged steelhead returned to the FCF a year after they were originally tagged. Evaluations at the FCF showed that the structure was not efficient at collecting adult salmon. During 2008–2009, 9 radio-tagged coho salmon and 11 radio-tagged steelhead were released to observe behavior near the facility and to estimate the recapture rate in the FCF. None of the tagged coho salmon were recaptured and only 27 percent of the tagged steelhead were recaptured. Additionally, we observed fish behavior at the FCF with an acoustic camera and found that relatively large numbers (>100 fish/sampling period) of adult salmon entered the FCF but similar numbers of fish exited during these periods as well. This suggested that the efficacy of the FCF was low. Our study was limited by the number of fish that could be handled each year and the number of transmitters that could be purchased annually, but our evaluations provided the first empirical data on adult salmon behavior and movement patterns in the Toutle River since the 1980 eruption of Mount St. Helens. Since the completion of this work, the U.S. Army Corps of Engineers has altered the SRS spillway and sediment plain; however, our results do provide information to assist fishery managers tasked with the complex management of wild salmon populations in the Toutle River. Future evaluations of juvenile and adult salmon behavior and movement likely will be required to effectively manage these populations in this complex system.

Washington↗

Surface-water quality and suspended-sediment quantity and quality within the Big River Basin, southeastern Missouri, 2011-13

Missouri was the leading producer of lead in the United States—as well as the world—for more than a century. One of the lead sources is known as the Old Lead Belt, located in southeast Missouri. The primary ore mineral in the region is galena, which can be found both in surface deposits and underground as deep as 200 feet. More than 8.5 million tons of lead were produced from the Old Lead Belt before operations ceased in 1972. Although active lead mining has ended, the effects of mining activities still remain in the form of large mine waste piles on the landscape typically near tributaries and the main stem of the Big River, which drains the Old Lead Belt. Six large mine waste piles encompassing more than 2,800 acres, exist within the Big River Basin. These six mine waste piles have been an available source of trace element-rich suspended sediments transported by natural erosional processes downstream into the Big River. A study was performed by the U.S. Geological Survey in cooperation with U.S. Environmental Protection Agency, Region 7, to calculate and characterize suspended-sediment quantity and quality within the Big River basin after reclamation of the mine waste piles ended in 2012. Streamflow and suspended sediments were quantified and sampled at two locations along a 68-mile reach of the Big River between Bonne Terre and Byrnes Mill, Missouri. The results will help regulatory agencies, such as the U.S. Environmental Protection Agency and U.S. Fish and Wildlife Service, determine impaired reaches and ecosystems for remedial and restoration efforts. Continuous stream stage, water temperature, and turbidity, and discrete suspended-sediment concentration data were collected at the two sites between October 2011 and September 2013. Suspended-sediment samples were collected during various hydrologic conditions to develop a regression model between discrete suspended-sediment concentration and continuous turbidity. Suspended sediments collected during stormflow events were analyzed for concentrations of trace elements such as barium, cadmium, lead, and zinc within two sediment size fractions. Event loads and annual loads of suspended sediment and select trace elements in suspended sediments also were calculated. Suspended-sediment loads computed by the regression model increased downstream from about 201,000 tons at the upstream site to about 355,000 tons at the downstream site during the study period. Stormflow-event-based (hereinafter referred to as “event-based”) suspended-sediment loads ranged from 180 to 32,000 tons at the upstream sampling site and 390 to 53,000 tons at the downstream site along the Big River. Although only seven stormflow events at the upstream site and six at the downstream site were sampled, the event-based suspended-sediment loads accounted for nearly 30 percent of the total suspended-sediment loads computed at both sites, indicating most of the suspended sediment transported through the Big River occurs during higher streamflows. Sediment quality guidelines, known as the threshold effect concentration and the probable effect concentration, used to assess toxicity of trace-element concentrations in sediments were compared to the cadmium, lead, and zinc concentrations in suspended sediment samples collected during stormflow events. All concentrations of cadmium, lead, and zinc in event-based suspended sediment samples exceeded the threshold and probable effect concentrations. Lead and zinc concentrations in the sediment size fraction less than 0.063 millimeters also exceeded the toxic effect threshold, above which sediment is considered to be heavily polluted causing adverse effects on sediment-dwelling organisms. Concentrations of cadmium and zinc in event-based suspended sediment samples were notably higher in samples from the upstream site than samples from the downstream site, indicating the sources of sediments enriched in these trace elements decrease in the downstream area of the watershed. The reduction in concentration of cadmium and zinc could be from dissolution of the constituents during transport or possibly a decrease in downstream source material. The lead concentration exceedance of the probable effects concentration as well as the threshold effects concentration indicates that lead-rich suspended sediments in the fraction less than 0.063 millimeters are readily available within the Big River Basin for transport. These sediments remain in the system from historical mining, and as the reclamation of mine waste piles in the upstream area of the watershed reduce additional sediment loadings, these fine sediments may be continually released as the river scours the streambed and erodes stream banks causing the lead-rich suspended sediment to remain in a state of equilibrium. Barium concentrations in suspended-sediments were nearly twice as high in stormflow event samples collected at the downstream site as compared to samples from the upstream site. The source of barium in the Big River could be from Mineral Fork and Mill Creek, which flow through the historical barite (barium sulfate, also known as tiff) mining district in Washington County, and discharge into the Big River between the two study sites. Total trace-element loads and yields in suspended sediments were computed from the sampled events for each year in the study. The total barium loads in suspended sediments were higher for sampled events collected at the downstream site than the upstream site during both study years. Cadmium and zinc loads in suspended sediments were lower at the downstream site than the upstream site, although the decrease in total load was not substantial during the study period. Lead loads in suspended sediments were lower at the downstream site during the first study year, with a slightly higher load downstream in the second year though the increase from upstream to downstream was small. Event-based yields were higher at the upstream site, indicating that readily available sediment sources are closer to the upstream site where more mining affected areas are located. The estimates determined during large precipitation events indicate that large sources of suspended sediments with large concentrations of trace elements are still available for transport within the Big River.

Missouri↗

Native Prairie Adaptive Management: a multi region adaptive approach to invasive plant management on Fish and Wildlife Service owned native prairies

Much of the native prairie managed by the U.S. Fish and Wildlife Service (FWS) in the Prairie Pothole Region (PPR) of the northern Great Plains is extensively invaded by the introduced cool-season grasses, smooth brome ( Bromus inermis ) and Kentucky bluegrass ( Poa pratensis ). Management to suppress these invasive plants has had poor to inconsistent success. The central challenge to managers is selecting appropriate management actions in the face of biological and environmental uncertainties. In partnership with the FWS, the U.S. Geological Survey (USGS) developed an adaptive decision support framework to assist managers in selecting management actions under uncertainty and maximizing learning from management outcomes. This joint partnership is known as the Native Prairie Adaptive Management (NPAM) initiative. The NPAM decision framework is built around practical constraints faced by FWS refuge managers and includes identification of the management objective and strategies, analysis of uncertainty and construction of competing decision models, monitoring, and mechanisms for model feedback and decision selection. Nineteen FWS field stations, spanning four states of the PPR, have participated in the initiative. These FWS cooperators share a common management objective, available management strategies, and biological uncertainties. Though the scope is broad, the initiative interfaces with individual land managers who provide site-specific information and receive updated decision guidance that incorporates understanding gained from the collective experience of all cooperators. We describe the technical components of this approach, how the components integrate and inform each other, how data feedback from individual cooperators serves to reduce uncertainty across the whole region, and how a successful adaptive management project is coordinated and maintained on a large scale. During an initial scoping workshop, FWS cooperators developed a consensus management objective: increase the composition of native grasses and forbs on native sod while minimizing cost. Cooperators agreed that decision guidance should be provided annually and should account for local, real-time vegetation conditions observed on the ground. Over the course of development, two prototypes of the decision framework were considered. The final framework recognized four alternative actions that managers could take in any given year: (1) Graze—targeted use of grazing ungulates to achieve defoliation, (2) Burn—application of prescribed fire as the single form of defoliation, (3) Burn/Graze—a combination treatment, and (4) Rest—no action. The study area included northern mixed-grass and tallgrass prairie. Native vegetation in mixed–grass prairie has a strong cool-season component and thus the dominant native species have a phenology similar to that of smooth brome and Kentucky bluegrass, making management of those species challenging. In contrast, tallgrass prairie has a strong warm-season native component, leading to an existence of cool-season windows, periods of time in the fall and spring when cool‐season invasive grass species are actively growing and vulnerable to damage via select management actions, but warm‐season grass species are not active and are thus less susceptible to damage via the same actions. This dichotomy between prairie types necessitated the development of separate but parallel decision support systems for mixed-grass and tallgrass biomes. Management units are parcels of native prairie that receive a single management treatment at any one time over their entire extent. At any particular time, the vegetation state of each management unit is characterized by the amount of cover of native grasses and forbs and the type of invasive grass that is dominant. In addition, each unit has a defoliation state which reflects the number of years since the last defoliation event and an index to how intensively the unit was managed during the previous 7 years. State-transition models are used to predict the state of a management unit in year t+1 from its state in year t and a prescribed management action that was applied between the two monitoring events. Alternative models are built around key uncertainties that make choice of a management action difficult. Three uncertainties revolve around whether the effect of management actions depends on (1) type of dominant invader, (2) past defoliation history, and (3) level of invasion. Two additional uncertainties are considered when choosing a management action for tallgrass units: (4) the effectiveness of grazing within the cool-season window as a surrogate for burning when smooth brome is the dominant invader, and (5) the differential effect of active management outside the window as compared to rest. Because data on the probability of transitioning from one state to another under the various models were lacking, expert opinion and elicitation were used to parameterize the models. In addition, cooperators participated in elicitation exercises to extract their beliefs regarding the value of having native prairie compared to the cost of achieving it. Quantifying the subjective expression of utility in this way allowed for mathematical representation of the management objective into an objective function. By maximizing the objective function, cumulative utility is maximized, leading to the identification of a sequence of decisions that will achieve the management objective. The NPAM system adopted a vegetation monitoring protocol that was rapid, inexpensive, and familiar to many of the cooperators. The monitoring protocol served three purposes: (1) determining current vegetation and defoliation states of each unit, (2) evaluating progress toward the management objective, and (3) assessing predictive performance of the alternative models. The management year runs from September 1 to August 31. Management can be applied anytime during that period and monitoring takes places from late June to mid-August. Cooperators enter vegetation data and management information into a centralized database by August 25 of each year. Given the current state of the system (vegetation and defoliation states) and the current understanding of the system (or the belief state), identifying the current best management decision is a matter of looking up the combination (that is, system state and belief state) in the appropriate (mixed-grass or tallgrass) optimal decision table. Given complete uncertainty at the outset of decision-making, initial assignment of equal belief weights to each model was believed reasonable. The decisions in the optimal decision table that correspond to the current belief state constitute the current optimal decision policy. By August 31 of each year, individual cooperators are provided with a recommended management action for each of their management units for the upcoming management year. Upon receiving the management recommendations for their units, managers consider the recommendation, along with other relevant information, and at some point during the year one of the management alternatives is carried out. This iterative cycle of making and implementing a management decision, predicting the response, monitoring the outcome, comparing predicted and observed outcomes, updating model weights, and recommending a management action for the next cycle is expected to result in an accumulation of weight on a representative model of system dynamics, thereby increasing understanding needed to effectively manage native prairies. The NPAM system is now entering its second full year of complete operation, and represents one of only a few fully implemented applications of adaptive management within the U.S. Fish and Wildlife Service. NPAM is truly unique in that it originated from the ground up as a result of the leadership and steadfastness of several refuge biologists and managers confronted with a common problem. These biologists recognized that working together across a large landscape presented perhaps the best opportunity for halting and reversing the invasion of native grasslands by non-native cool-season grasses. Importantly, the NPAM system encapsulates the collective thinking and experience of tens if not hundreds of individuals who have battled this vexing problem for much of their careers. The NPAM initiative is rooted in principles of adaptive management, thereby affording the opportunity for grassland managers to pursue management objectives while acquiring information to reduce uncertainty and improve future management. The project introduced a number of technical innovations that will serve as templates for conservation efforts throughout and beyond the U.S. Fish and Wildlife Service. First, NPAM is an on-the-ground implementation of active adaptive management—possibly the first of its kind in conservation management—in which recommended management actions result from a prospective analysis of future learning (Williams, 1996). Second, by the use of dynamic optimization, NPAM demonstrates how decisions can be made that take into account possible future transitions of the system. Third, NPAM demonstrates how models of partial controllability are an effective means of accommodating unpredictable circumstances that cause a manager to follow a different course than was intended. Finally, the database developed for NPAM is an unparalleled system that enables the rapid integration of data from the field for the generation of ‘just-in-time’ management recommendations. In all, NPAM provides an example of how a science-management partnership can be forged to achieve large-scale conservation objectives.

Minnesota;Montana;North Dakota;South Dakota↗