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The 3D Elevation Program—Supporting Wisconsin’s economy

Introduction In Wisconsin, high-quality elevation data can be utilized for improving agriculture and precision farming, natural resources conservation, and water supply planning, as well as management of flood risk, infrastructure, construction, water quality, forest resources, and many other business uses. Such data can be beneficial for the State’s responses to large rain events, flooding, coastal erosion along the Great Lakes, and urban and suburban development. Critical applications that meet the State’s management needs depend on light detection and ranging (lidar) data that provide a highly detailed three-dimensional (3D) model of the Earth’s surface and aboveground features. The 3D Elevation Program (3DEP; refer to sidebar) is managed by the U.S. Geological Survey (USGS) in partnership with Federal, State, Tribal, U.S. territorial, and local agencies to acquire consistent lidar coverage at quality level 2 or better (table 1) to meet the many needs of the Nation and Wisconsin. The status of available and in-progress 3DEP baseline lidar data in Wisconsin is shown in figure 1. 3DEP baseline lidar data include quality level 2 or better, 1-meter or better digital elevation models, and lidar point clouds, and must meet the Lidar Base Specification 2025 Rev. A (https://www.usgs.gov/3dep/lidarspec) or newer requirements. The National Enhanced Elevation Assessment (Dewberry, 2012) identified user requirements and conservatively estimated that availability of lidar data would result in at least $11.18 million in new benefits annually to the State. The top 10 Wisconsin business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown in table 2.

Wisconsin↗

FLOwPER user guide—For collection of FLOw PERmanence field observations

The accurate mapping of streams and their streamflow conditions in terms of presence or absence of surface water is important to both understanding physical, chemical, and biological processes in streams and to managing land, water, and ecological resources. This document describes a field form, FLOwPER (FLOw PERmanence), available within a mobile application (app), for standardized data collection of the presence or absence of surface flow in streams. The FLOwPER Database is a publicly available geodataset that can be used for research and management applications. This document provides instructions on how to (1) access and download the FLOwPER field form within the mobile app service, (2) use and complete a FLOwPER field form, and (3) view and download data from the FLOwPER Database.

Open-File Report↗

Assessment of soil and water resources in the Organ Mountains-Desert Peaks National Monument, New Mexico

The Organ Mountains-Desert Peaks National Monument (Monument) in southern New Mexico was established in 2014. Given anticipated future demands in the Monument for recreation, livestock grazing, and maintenance of rights-of-way (for example, pipelines and powerlines), the Bureau of Land Management (BLM) needs a better understanding of the current soil and water resources and how infrastructure improvements could affect these resources and the watershed. Specifically, the BLM is concerned with infiltration and erosion and their relations to existing or planned infrastructure, such as roads, campgrounds, location of livestock grazing, and rights-of-way. Alternatives to the current land-use conditions, land-management practices, and infrastructure will be assessed by BLM to best protect Monument resources. The U.S. Geological Survey, in cooperation with the BLM, conducted a study to assess the soil and water resources within the Monument to provide an inventory and compilation of natural-resource information needed by resource managers for the BLM’s land-use planning process for this new national monument. The overall objectives of this study were to (1) compile and interpret existing soil- and water-resource data for the Monument and (2) provide a basic assessment of the surface hydrological effects of selected alternatives to current land use and infrastructure. Data were compiled by using geographic information system software and evaluated for hydrologic and landscape properties that influence infiltration, runoff, and erosion. The effects of changing vegetation were simulated by using different scenarios in the Rangeland Hydrology and Erosion Model. Results of this model indicate areas where soil loss or runoff may occur.

New Mexico↗

Selected hydrologic data for Pahvant Valley and adjacent areas, Millard County, Utah, 1987

This report contains hydrologic data collected in Pahvant Valley and adjacent areas from 1909 to 1987. The report area is mainly comprised of Pahvant Valley on the east and the southern part of the Sevier Desert on the west (plate 1). The area is in west-central Utah, within the Basin and Range physiographic province, and includes about 1,600 square miles. Most of the data in this report were collected by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights, from 1985 to 1987. Some of the earlier data were previously published by Enright and Holmes (1982), Meinzer (1911), Mower (1963 and 1967), and Mundorff (1970). The purpose of this report is to provide hydrologic data for use by the general public and by officials managing the area's water resources, and to supplement interpretive reports for the area. Tables 1 to 6 contain information about wells including well completions, drillers' logs, water levels, flowing-well discharges, and chemical quality. Spring and surfacewater site data are listed in tables 7 to 9. Hydrologic-data sites are shown on plate 1.

Utah↗

Potentiometric surfaces, 2011–12, and water-level differences between 1995 and 2011–12, in wells of the “200-foot,” “500-foot,” and “700-foot” sands of the Lake Charles area, southwestern Louisiana

Water levels were determined in 90 wells to prepare 2011–12 potentiometric surfaces focusing primarily on the “200-foot,” 500-foot,” and “700-foot” sands of the Lake Charles area, which are part of the Chicot aquifer system underlying Calcasieu and Cameron Parishes of southwestern Louisiana. These three aquifers provided 34 percent of the total water withdrawn and 93 percent of the groundwater withdrawn in Calcasieu and Cameron Parishes in 2012 (84.5 million gallons per day [Mgal/d]). This work was completed by the U.S. Geological Survey, in cooperation with the Louisiana Department of Transportation and Development, to assist in developing and evaluating groundwater-resource management strategies. The highest water levels determined in wells screened in the “200-foot,” “500-foot,” and “700-foot” sands were about 8 feet (ft) above the National Geodetic Vertical Datum of 1929 (NGVD 29), 2 ft below NGVD 29, and 14 ft below NGVD 29, respectively, and were located in northwestern Calcasieu Parish. The lowest water levels determined in wells screened in the “200-foot,” “500-foot,” and “700-foot” sands were approximately 50, 80, and 70 ft below NGVD 29, respectively, and were located in the southern Lake Charles metropolitan area, to the west of Prien Lake, and between the cities of Lake Charles and Sulphur, respectively. The primary groundwater flow direction in these three aquifers was radially towards pumping centers overlying the water-level lows. Comparisons of water-level differences in 42 wells measured in 1995 and 2011–12 indicated that the maximum increases in water levels for wells screened in the “200-foot,” “500-foot,” and “700-foot” sands were approximately 7, 31, and 19 ft, respectively. Water-level increases coincided with a decline in total groundwater withdrawals during the period (about 25 Mgal/d from 1995 to 2012) from these sands. More specifically, withdrawals from the “500-foot” sand affected water levels in wells screened in the “200-foot” and “700-foot” sands because the three are hydraulically connected and withdrawals from the “500-foot” sand were greater by volume than withdrawals from the “200-foot” and “700-foot” sands.

Louisiana↗

A Science Plan for a Comprehensive Regional Assessment of the Atlantic Coastal Plain Aquifer System in Maryland

The Maryland Coastal Plain region is, at present, largely dependent upon ground water for its water supply. Decades of increasing pumpage have caused ground-water levels in parts of the Maryland Coastal Plain to decline by as much as 2 feet per year in some areas of southern Maryland. Continued declines at this rate could affect the long-term sustainability of ground-water resources in Maryland's heavily populated Coastal Plain communities and the agricultural industry of the Eastern Shore. In response to a recommendation in 2004 by the Advisory Committee on the Management and Protection of the State's Water Resources, the Maryland Geological Survey and the U.S. Geological Survey have developed a science plan for a comprehensive assessment that will provide new scientific information and new data management and analysis tools for the State to use in allocating ground water in the Coastal Plain. The comprehensive assessment has five goals aimed at improving the current information and tools used to understand the resource potential of the aquifer system: (1) document the geologic and hydrologic characteristics of the aquifer system in the Maryland Coastal Plain and appropriate areas of adjacent states; (2) conduct detailed studies of the regional ground-water-flow system and water budget for the aquifer system; (3) improve documentation of patterns of water quality in all Coastal Plain aquifers, including the distribution of saltwater; (4) enhance ground-water-level, streamflow, and water-quality-monitoring networks in the Maryland Coastal Plain; and (5) develop science-based tools to facilitate sound management of the ground-water resources in the Maryland Coastal Plain. The assessment, as designed, will be conducted in three phases and if fully implemented, is expected to take 7 to 8 years to complete. Phase I, which was initiated in January 2006, is an effort to assemble all the information and investigation tools needed to do a more comprehensive assessment of the aquifer system. The work will include updating the hydrogeologic framework, developing a Geographic Information System-based aquifer information system, refinement of water-use information, assessment of existing water-quality data, and development of detailed plans for ground-water-flow and management models. Phase II is an intensive study phase during which a regional ground-water-flow model will be developed and calibrated for the entire region of Maryland in the Atlantic Coastal Plain as well as appropriate areas of Delaware and Virginia. The model will be used to simulate flow and water levels in the aquifer system and to study the water budget of the system. The model analysis will be based on published information but will be supplemented with field investigations of recharge and leakage in the aquifer system. Localized and finely discretized ground-water-flow models that are embedded in the regional model will be developed for selected areas of heavy withdrawals. Other modeling studies will be conducted to better understand flow in the unconfined parts of the aquifer system and to support the recharge studies. Phase II will also include selected water-quality studies and a study to determine how hydrologic and water-quality-monitoring networks need to be enhanced to appropriately assess the sustainability of the Coastal Plain aquifer system. Phase III will be largely devoted to the development and application of a ground-water optimization model. This model will be linked to the ground-water-flow model to create a model package that can be used to test different water-management scenarios. The management criteria that will be used to develop these scenarios will be determined in consultation with a variety of state and local stakeholders and policy makers in Phases I and II of the assessment. The development of the aquifer information system is a key component of the assessment. The system will store all relevant aquifer data

Open-File Report↗

Groundwater and surface-water interactions in the Waihe‘e-Kahalu‘u watershed, O‘ahu, Hawai‘i—Analysis of historical data and numerical groundwater-model simulations

The Waihe‘e-Kahaluʻu watershed and surrounding areas lie in a dike-impounded groundwater setting of the Ko‘olau Range, O‘ahu, Hawai‘i, where groundwater withdrawal from wells and tunnels have resulted in reductions in streamflow. Resource managers and surface-water users seek information that can be used to balance the needs of competing uses of groundwater and streamflow in the watershed. This study assesses the effects of four groundwater developments in the Waihe‘e-Kahalu‘u watershed—Kahaluu Tunnel, Waihee Tunnel, Kahaluu Well, and Waihee Incline Wells—on Kahalu‘u and Waihe‘e Streams. Analyses of historical streamflow, withdrawal, and rainfall data indicate that base flow (the component of streamflow that is supplied from groundwater discharge) in Kahalu‘u and Waihe‘e Streams decreased in response to withdrawals from wells and tunnels within and outside the watershed. Groundwater-model simulations indicate that shutdown of selected tunnels and wells in the Waihe‘e-Kahaluʻu watershed will result in increases of groundwater discharge, but not all of the increase will occur in streams within the watershed; increases will also occur in streams outside the basin, the ocean, and tunnels other than those that were shut down. The analysis of historical data and model simulations is consistent in showing that the effects of withdrawal changes on streams are not constrained by the topographic boundaries of watersheds. Stream base flows in the Waihe‘e-Kahalu‘u watershed are subject to a complex interaction of multiple withdrawals from wells and tunnels installed at various times within and outside the watershed. The correspondence between withdrawals and base-flow changes is consistent with the conceptual model and understanding of the connection between groundwater and streamflow in the dike-impounded groundwater setting of the Waihe‘e-Kahalu‘u watershed and the Ko‘olau Range.

Hawaii↗

Science programs in Kansas

The U.S. Geological Survey (USGS) is a non-regulatory Earth science agency within the Department of the Interior that provides impartial scientific information to describe and understand the health of our ecosystems and environment; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life. The USGS cooperates with Federal, State, tribal, and local agencies in Kansas to deliver long-term data in real-time and interpretive reports describing what those data mean to the public and resource management agencies. USGS science programs in Kansas provide real-time groundwater monitoring at more than 19 locations; streamflow monitoring at more than 216 locations; water-quality and trends in the Little Arkansas and Kansas Rivers; inflows and outflows of sediment to/from reservoirs and in streams; harmful algal bloom research in the Kansas River, Milford Lake, and Cheney Reservoir; water-quantity and water-quality effects of artificial groundwater recharge for the Equus Beds Aquifer Storage and Recovery project near Wichita, Kansas; compilation of Kansas municipal and irrigation water-use data statewide; the occurrence, effects, and movement of environmental pesticides, antibiotics, algal toxins, and taste-and-odor compounds; and funding to the Kansas Water Resources Research Institute to further research and education through Kansas universities.

Kansas↗

Data standardization. The key to effective management

Effective management of the nation's water resources is dependent upon accurate and consistent hydrologic information. Before the emergence of environmental concerns in the 1960's, most hydrologic information was collected by the U.S. Geological Survey and other Federal agencies that used fairly consistent methods and equipment. In the past quarter century, however, increased environmental awareness has resulted in an expansion of hydrologic data collection not only by Federal agencies, but also by state and municipal governments, university investigators, and private consulting firms. The acceptance and use of standard methods of collecting and processing hydrologic data would contribute to cost savings and to greater credibility of flow information vital to responsible assessment and management of the nation's water resources. This paper traces the evolution of the requirements and uses of open-channel flow information in the U.S., and the sequence of efforts to standardize the methods used to obtain this information in the future. The variable nature of naturally flowing rivers results in continually changing hydraulic properties of their channels. Those persons responsible for measurement of water flowing in open channels (streamflow) must use a large amount of judgement in the selection of appropriate equipment and technique to obtain accurate flow information. Standardization of the methods used in the measurement of streamflow is essential to assure consistency of data, but must also allow considerable latitude for individual judgement to meet constantly changing field conditions.

Conference Paper↗

An integrated hydrologic model to support the Central Platte Natural Resources District Groundwater Management Plan, central Nebraska

The groundwater and surface-water supply of the Central Platte Natural Resources District supports a large agricultural economy from the High Plains aquifer and Platte River, respectively. This study provided the Central Platte Natural Resources District with an advanced numerical modeling tool to assist with the update of their Groundwater Management Plan. An integrated hydrologic model, called the Central Platte Integrated Hydrologic Model, was constructed using the MODFLOW-One-Water Hydrologic Model code with the Newton solver. This code integrates climate, landscape, surface water, and groundwater-flow processes in a fully coupled approach. Model framework included 163 rows; 327 columns; 2,640 feet cell sides; and 3 vertical layers. A predevelopment model simulated steady-state hydrologic conditions prior to April 30, 1895, and a development period model discretized into 610 stress periods simulated transient hydrologic conditions from May 1, 1895, to December 31, 2016, using 170 biannual stress periods from 1895 to 1980, and monthly stress periods from May 1, 1980, to December 31, 2016. Calibration of the Central Platte Integrated Hydrologic Model involved two phases: a manual adjustment of parameters, followed by the automated calibration completed using BeoPEST that was facilitated by the employment of the singular value decomposition-assist features of PEST that specified 50 super parameters assembled from the 435 adjustable parameters and Tikhonov regularization. The average absolute groundwater-level residuals for model layers one, two, and three were 6.1, 12.4, and 7.4 feet, respectively. Calibrated horizontal hydraulic conductivity was about 70, 32, and 35 feet per day for layers 1, 2, and 3, respectively. The largest development period inflow to groundwater was recharge from deep percolation past the root zone, averaging 1,122,257 acre-feet per year (2.7 inches per year), and the largest outflow was to irrigation wells, averaging 693,171 acre-feet per year (10.2 inches per year for the Central Platte Natural Resources District). Other substantial groundwater outflows included evapotranspiration and base flow. For the total development period, there was a net change in storage of −122,393 acre-feet per year (−0.3 inch per year). The calibrated Central Platte Integrated Hydrologic Model was used to simulate eight different potential future climate and irrigation pumping conditions from January 1, 2017, to December 31, 2049. Simulated future groundwater levels within the Central Platte Natural Resources District varied significantly between scenarios and locally, from 13.8 feet below to 7.6 feet above baseline 1982 groundwater levels. Most areas exhibited groundwater-level declines for the drought scenarios and rises for the alternate irrigation scenarios. Changes in scenario groundwater levels correlated with the relations between farm net recharge and irrigation pumping. Linear “first order second moment” techniques indicated that the uncertainty in projected groundwater altitudes was reduced by 15.33 feet through model calibration.

Nebraska↗

Water-quality conditions and suspended-sediment transport in the Wilson and Trask Rivers, northwestern Oregon, water years 2012–14

In October 2011, the U.S. Geological Survey began investigating and monitoring water-quality conditions and suspended-sediment transport in the Wilson and Trask Rivers, northwestern Oregon. Water temperature, specific conductance, turbidity, and dissolved oxygen were measured every 15–30 minutes in both streams using real-time instream water-quality monitors. In conjunction with the monitoring effort, suspended-sediment samples were collected and analyzed to model the amount of suspended sediment being transported by each river. Over the course of the 3-year study, which ended in September 2014, nearly 600,000 tons (t) of suspended-sediment material entered Tillamook Bay from these two tributaries. Each year of the study, the Wilson River transported between 80,300 and 240,000 t of suspended sediment, while the Trask River contributed between 28,200 and 69,900 t. The suspended-sediment loads observed during the study were relatively small because streamflow conditions were routinely lower than normal between October 2011 and September 2014. Only one storm had a recurrence interval between a 2- and 5-year event. Every other storm produced streamflows equivalent to what would be classified as a 1- or 2-year event. Because most sediment moves during high flows, the lack of heavy rainfall and elevated streamflows muted any high sediment loads. Along with assessing suspended-sediment transport, the U.S. Geological Survey also monitored instream water quality. This monitoring was used to track instream conditions and relate them to water temperature, dissolved oxygen, and sedimentation issues for the Wilson and Trask Rivers. Stream temperatures in the Wilson and Trask Rivers exceeded the temperature standard for cold-water habitat. Water temperatures at both streams exceeded the standard for more than 30 percent of the year, as stream temperatures increased above the seasonal 13 degrees Celsius (°C) (seasonal core cold-water habitat) and 16 °C (salmon and steelhead [ Oncorhynchus mykiss ] spawning) thresholds. Conversely, dissolved oxygen concentrations rarely decreased to less than the absolute water-quality criterion of 8 milligrams per liter for cold-water streams. Results from this study will provide resource managers insight into the seasonality of water-quality conditions and the extent of suspended-sediment transport in the Wilson and Trask Rivers. The data are useful for establishing a baseline and for maintaining best-use land management practices and possibly for aiding in prioritization of restoration actions for both rivers and their respective watersheds.

Oregon↗

The 3D Elevation Program: Summary for South Dakota

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of South Dakota, elevation data are critical for agriculture and precision farming, natural resources conservation, water supply and quality, infrastructure and construction management, flood risk management, geologic resource assessment and hazard mitigation, and other business uses. Today, high-density light detection and ranging (lidar) data are the primary sources for deriving elevation models and other datasets. Federal, State, tribal, and local agencies work in partnership to (1) replace data that are older and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment (NEEA; Dewberry, 2011) evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 for the conterminous United States and quality level 5 ifsar data for Alaska with a 6- to 10-year acquisition cycle provided the highest benefit/cost ratios.The new 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey, the Office of Management and Budget Circular A–16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other 3D representations of the Nation’s natural and constructed features.

South Dakota↗

The 3D Elevation Program: summary for North Dakota

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of North Dakota, elevation data are critical for agriculture and precision farming, natural resources conservation, water supply and quality, infrastructure and construction management, flood risk management, geologic resource assessment and hazard mitigation, and other business uses. Today, high-density light detection and ranging (lidar) data are the primary sources for deriving elevation models and other datasets. Federal, State, Tribal, and local agencies work in partnership to (1) replace data that are older and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 for the conterminous United States and quality level 5 ifsar data for Alaska with a 6- to 10-year acquisition cycle provided the highest benefit/cost ratios.The 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey (USGS), the Office of Management and Budget Circular A–16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other 3D representations of the Nation’s natural and constructed features.

North Dakota↗

Evaluating drought risk of the Red River of the North Basin using historical and stochastic streamflow upstream from Emerson, Manitoba

Drought and its effect on streamflow are important to understand because of the potential to adversely affect water supply, agricultural production, and ecological conditions. The Red River of the North Basin in north-central United States and central Canada is susceptible to dry conditions. During an extended drought, streamflow conditions in the Red River of the North may become inadequate to support existing water supply needs in the basin for agriculture, industry, human use, and aquatic life. To understand potential future low-streamflow conditions in the Red River of the North Basin, the U.S. Geological Survey, in cooperation with the International Joint Commission, North Dakota Department of Water Resources, Red River Joint Water Resource District, and Red River Watershed Management Board, developed a water-balance model of the Red River of the North Basin upstream from Emerson, Manitoba, Canada, and coupled the model with stochastic weather inputs to simulate possible future low-streamflow conditions. Historical changes in low-streamflow conditions were characterized across the Red River of the North Basin using multiple change-point analysis for 12 streamgages. Across these stations, significant change-point years in 1943 and 1994 marked increases in the magnitude of low-streamflow conditions. During 1920–2015, conversion of primary land (not affected by human use) to agricultural and secondary land was followed by a conversion from smalls grains to corn and soybeans as the dominant crop type. From land-use analysis, 1940–2000 was determined to have relatively stable land use and therefore was used as the calibration period for the water-balance model. A deterministic water-balance model was developed for the Red River of the North Basin upstream from Emerson, Manitoba. The water-balance model was calibrated with data from 37 U.S. Geological Survey streamgages for 1940–2000 and verified using data for 2001–15. The calibrated water-balance model simulated streamflow distributions that mirrored the seasonal patterns of the observed mean monthly streamflow and the standard deviation of the monthly streamflow data, especially during the fall and winter months when streamflow was lowest. For the verification period, during the low-streamflow months of December through January, the difference between simulated and observed data was similar to the calibration comparison and successfully reproduced seasonal trends in the distribution of streamflow, even when using weather data that were outside the calibration period. To determine the future risk of low-streamflow conditions in the Red River of the North Basin, a block-bootstrap method was used to generate multiple possible future climates. These stochastically generated weather time series were then input to a water-balance model to simulate a distribution of possible streamflows. Three sets of experiments were performed, with each experiment containing a set of scenarios. The first set of experiments from the stochastic streamflow model were designed to investigate how changes in reservoir management would affect the distribution of low streamflow. Relative to scenario 1 (present-day [2023] reservoir operation), scenario 2 (no reservoir operation) shifted the low-streamflow frequency curves downward, reducing the annual minimum monthly streamflow for the Emerson subbasin. Subbasins were defined by the contributing area upstream from a selected streamgage station. Relative to scenario 1, scenario 3 (regulated streamflow with an increased reservoir capacity of 10 percent) shifted the low-streamflow frequency curves upward for the Emerson subbasin. The magnitude of this upward shift, caused by increased reservoir capacity, was lower than the magnitude of the shift caused by the absence of the reservoirs, which indicates that the streamflow was most affected when the reservoirs were first constructed. The second set of experiments from the stochastic streamflow model included two scenarios that were performed to better understand how the Red River of the North Basin responds to long periods of low or high precipitation. The results indicate that the model consistently overestimated streamflow, but the relative change between a wet and dry climate state of simulated streamflow distribution reasonably matched the relative change of historical streamflow. Across the subbasins, the model was most accurate for low-streamflow conditions associated with nonexceedance probabilities between 20 and 40 percent. The third set of experiments from the stochastic streamflow model were done to investigate low-streamflow response across the basin to several drought events. Low-end streamflow was reduced when the basin was exposed to a drought, and the magnitude of the reduction increased with longer or more intense droughts. Compared to the low-intensity drought scenarios, the range of percent reductions (as indicated by the interquartile range) was larger for the high-intensity drought scenarios for all subbasins, and the subbasins of Grand Forks and Emerson had a smaller range of reductions compared to the other three subbasins. The larger drainage area—combined with the large contribution of the Red Lake River and several other Minnesota tributaries that generally experience wetter climate conditions—upstream from the Emerson and Grand Forks subbasins may contribute to the smaller range in reductions under the high intensity scenarios. Comparison of the percent reduction in low-end streamflow among subbasins also indicated that the effects of drought duration and intensity could be cumulative. Combining factors of time and intensity produced a larger reduction in streamflow than when each effect was isolated. The array of drought scenarios can be used to determine how a subbasin would respond to multiple possible future conditions. Based on climate predictions, the drought scenario that best matches a future anticipated drought scenario can be used to estimate a low streamflow response for a given subbasin.

Manitoba, Minnesota, North Dakota↗

Decision-making for managing harmful algal blooms

Cyanobacteria are a global water-quality concern because these organisms can develop into harmful blooms that affect ecologic, economic, and public health. U.S. Geological Survey scientists worked with the New York State Office of Parks, Recreation and Historic Preservation and the New York State Department of Environmental Conservation to develop a structured decision-making template for managing cyanobacterial harmful algal blooms. This approach can help natural resource managers make decisions to manage water bodies threatened by harmful algal blooms.

New York↗

National Water-Quality Assessment Program: the Northern New England Basins study unit

In 1991, the U.S. Geological Survey (USGS), U.S. Department of the Interior, began a full-scale National Water-Quality Assessment (NAWQA) program. The objectives of the NAWQA program are to describe the present and future water quality of large, representative parts of the United States's surface- and ground-water resources and to identify the primary natural and man-made factors that affect the quality of these resources. The final product of the program will be information that may be used by water-resource policy makers and managers at national, State, and local levels. The NAWQA program encompasses 60 study units. These units are delineated by hydrologic systems that include parts of most of the Nation's major river basins and aquifer systems. Study units range in size from 1,000 mi 2 (square miles) to more than 60,000 mi 2 and represent 60 to 70 percent of the Nation's water use and population served by public water supplies. The first group of 20 study-unit investigations began in 1991. A second group of 20 study-unit investigations began in 1994, which includes the Northern New England Basins study unit.

Maine;Massachusetts;New Hampshire↗

Aquatics Systems Branch: transdisciplinary research to address water-related environmental problems

The Aquatic Systems Branch at the Fort Collins Science Center is a group of scientists dedicated to advancing interdisciplinary science and providing science support to solve water-related environmental issues. Natural resource managers have an increasing need for scientific information and stakeholders face enormous challenges of increasing and competing demands for water. Our scientists are leaders in ecological flows, riparian ecology, hydroscape ecology, ecosystem management, and contaminant biology. The Aquatic Systems Branch employs and develops state-of-the-science approaches in field investigations, laboratory experiments, remote sensing, simulation and predictive modeling, and decision support tools. We use the aquatic experimental laboratory, the greenhouse, the botanical garden and other advanced facilities to conduct unique research. Our scientists pursue research on the ground, in the rivers, and in the skies, generating and testing hypotheses and collecting quantitative information to support planning and design in natural resource management and aquatic restoration.

Fact Sheet↗

Managing water in the West: developing new tools for a critical resource

Rapid population growth in the Western United States over the last century has placed increasing strains on our water supplies and aquatic ecosystems. Historically, water rights have been used to determine the allocation of water in the West, but rules and regulations related to endangered species now often drive how water is released from reservoirs in large rivers such as the lower Colorado and the Columbia. In numerous smaller watersheds, communities are trying to balance the water necessary for human use, irrigation, and the conservation of ecosystems. To assist managers in the face of increasing complexity and uncertainty in water management decision-making, the Western Fisheries Research Center (WFRC) is involved in developing a new generation of integrative tools. Below are some examples of the types of tools that already exist within the WFRC.

Fact Sheet↗