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Simulated response of the Sparta Aquifer to outcrop area recharge augmentation, southeastern Arkansas

Recharge augmentation by construction of infiltration impoundments is a potential means of increasing aquifer water levels and aquifer yield that is under consideration for the Sparta aquifer in southeastern Arkansas. The aquifer is a major water resource for municipal, industrial, and agricultural uses, and approximately 287 million gallons per day was pumped from the aquifer in Arkansas in 1995; this is double the amount pumped in 1975. Historically, the Sparta aquifer has provided abundant water of high quality. In recent years, however, the demand for water in some areas has resulted in withdrawals from the Sparta that significantly exceed recharge to the aquifer, and considerable declines have occurred in the potentiometric surface. To better manage the Sparta aquifer, water users in Arkansas are evaluating and implementing a variety of management practices and assessing alternative, surface-water sources to reduce stress upon the Sparta aquifer. One approach to managing and maximizing use of the Sparta aquifer is augmenting recharge to the aquifer by construction of infiltration lakes or canals within the recharge area. The basic concept of augmented recharge is simply to increase the amount of water being introduced into the aquifer so that more water will be available for use. Ground-water flow model simulations were conducted to assess the effectiveness of constructing lakes or canals to augment recharge. Results show that construction of five new lakes in the Sparta recharge area upgradient from major pumping centers or construction of a series of canals along the length of the recharge area yield notable benefit to aquifer conditions when compared with simulations entailing no augmentation of recharge. Augmentation of recharge in the Sparta aquifer with emplacement of lakes provides slight increase to aquifer water levels. The presence of the lakes increased simulated aquifer water levels 0.5 foot or more across a broad area comprising all or a substantial part of 19 counties after the 30-year simulation period. Substantial increases of 5 feet or greater are limited to a smaller area proximal to the lakes. Increases of 5 feet or more are seen in El Dorado, Pine Bluff, and Stuttgart. The positive effect of the lakes on aquifer water levels is rapidly realized after emplacement of the lakes. For example, in the El Dorado area more than 3 feet of a total of 8 feet of water-level increase is seen in the first 5 years of the simulation; in the Pine Bluff area 9 feet of a total of 16 feet of increase occurs within 5 years. Sustainable yield from the aquifer could be expected to be increased within the zone of influence of the lakes. Augmentation of recharge in the Sparta aquifer with emplacement of canals provides considerable increase of aquifer water levels. The zone of influence in the aquifer with canal-augmented recharge extends from the recharge area eastward to the Mississippi River. Aquifer water levels exhibit an increase of 5 feet or more across a broad area comprising all or a substantial part of 15 counties. Increases of 20 feet or more are seen in El Dorado, Pine Bluff, and Stuttgart. The amount of water moving into the aquifer is substantially increased under this scenario, and the amount of water removed from storage is decreased, thereby, increasing aquifer conditions considerably. Sustainable yield from the aquifer could be expected to be greater within the zone of influence of the canals as compared to either the scenario without recharge augmentation or recharge augmentation with lakes. The effect of the canal on aquifer water levels is rapidly realized after emplacement of the canals. For example, in the El Dorado area, 22 feet of a total of 30 feet of increase is seen in the first 5 years of the simulation; in the Pine Bluff area, 15 feet of a total of 24 feet of increase occurs within 5 years. As constructed, the model simulations imply that any lakes or canals constructed would maintain exce

Arkansas↗

Surface-Water, Water-Quality, and Ground-Water Assessment of the Municipio of Mayaguez, Puerto Rico, 1999-2002

The surface-water assessment portion of this study focused on analysis of low-flow characteristics in local streams and rivers, because the supply of safe drinking water was a critical issue during recent dry periods. Low-flow characteristics were evaluated at one continuous-record gaging station based on graphical curve-fitting techniques and log-Pearson Type III frequency curves. Estimates of low-flow characteristics for 20 partial-record stations were generated using graphical-correlation techniques. Flow-duration characteristics for the continuous- and partial-record stations were estimated using the relation curves developed for the low-flow study. Stream low-flow statistics document the general hydrology under current land use, water-use, and climatic conditions. A survey of streams and rivers utilized 37 sampling stations to evaluate the sanitary quality of about 165 miles of stream channels. River and stream samples for fecal coliform and fecal streptococcus analyses were collected on two occasions at base-flow conditions. Bacteriological analyses indicate that a significant portion of the stream reaches within the municipio of Mayaguez may have fecal coliform bacteria concentrations above the water-quality goal (standard) established by the Puerto Rico Environmental Quality Board (Junta de Calidad Ambiental de Puerto Rico) for inland surface waters. Sources of fecal contamination may include: illegal discharge of sewage to storm-water drains, malfunctioning sanitary sewer ejectors, clogged and leaking sewage pipes, septic tank leakage, unfenced livestock, and runoff from livestock pens. Long-term fecal coliform data from five sampling stations located within or in the vicinity of the municipio of Mayaguez have been in compliance with the water-quality goal for fecal coliform concentration established in July 1990. Geologic, topographic, soil, hydrogeologic, and streamflow data were compiled into a database and used to divide the municipio of Mayaguez into five hydrogeologic terranes. This integrated database then was used to evaluate the ground-water potential of each hydrogeologic terrane. Lineament-trace analysis was used to help assess the ground-water development potential in the hydrogeologic terranes containing igneous rocks. Analyses suggest that areas with slopes greater than 15 degrees have relatively low ground-water development potential. The presence of fractures, independent of the topographic slope, may locally enhance the water-bearing properties in the hydrogeologic terranes containing igneous rocks. The results of this study indicate that induced streamflow generally is needed to sustain low to moderate ground-water withdrawal rates in the five hydrogeologic terranes. The ground-water flow systems in the hydrogeologic terranes are only able to sustain small withdrawal rates that rarely exceed 50 gallons per minute. Areas with a high density of fractures, as could be the case at the intersection of lineament traces in the upper parts of the Rio Ca?as and Rio Yaguez watersheds, are worthy of exploratory drilling for ground-water development.

Water-Resources Investigations Report↗

The response of the Iao aquifer to ground-water development, rainfall, and land-use practices between 1940 and 1998, Island of Maui, Hawaii

Ground water pumped from the Iao aquifer has been used for agricultural purposes since 1948, and domestic purposes since 1955. In 1990, the Hawaii State Commission on Water Resource Management established a value of 20 million gallons per day for the sustainable yield of the aquifer. Water-level data from observation wells throughout the aquifer and information on the depth to and thickness of the transition zone between freshwater and saltwater at the Waiehu deep monitor well indicate that pumping rates near the sustainable yield value of 20 million gallons per day could result in saltwater intrusion in some pumped wells. Since the introduction of pumpage in 1948 and the reduction of recharge in 1980, water levels have declined, chloride concentrations of the pumped water have increased, and the transition zone between freshwater and saltwater has risen. Water levels declined by about 18 feet between 1940 and 1998 in the area near Iao Stream, and by as much as 6 feet between 1977 and 1997 in the vicinity of the major well fields near Waiehu Stream. Chloride concentrations of pumped water have risen at all the well fields, but are presently below the U.S. Environmental Protection Agency recommended standard of 250 milligrams per liter. The chloride concentration of water pumped from Mokuhau 2, however, was 460 milligrams per liter in late 1996 when pumping was halted at this well. The midpoint of the transition zone, as measured at the Waiehu deep monitor well, rose by about 108 feet between 1985 and 1998.

Hawaii↗

Ground-water hydrology of northern Napa Valley, California

The alluvium of northern Napa Valley is the principal aquifer of the area and is capable of yielding as much as 3,000 gallons per minute to wells. Generally the larger-yielding wells are along the Napa River where the alluvium is thickest and most permeable. Recharge to the alluvium is chiefly by percolation from streams and infiltration of precipitation. Discharge is chiefly flow to the Napa River, evapotranspiration, and pumpage from wells. Both recharge to, and discharge from, the alluvial aquifer are sensitively influenced by rainfall. About 190,000 acre-feet of water is presently (1972) stored in the alluvium of northern Napa Valley. Future annual water use in the project area will probably vary between 12,000 and 35,000 acre-feet and, for most purposes, can be supplied by the alluvial aquifer even during extended periods of limited rainfall. Generally low transmissivities in the alluvium, however, limit the opportunity for obtaining sustained, large yields from wells in much of the valley and require that large-scale development and operation of wells in much of the area be planned and synchronized. Sustained drought conditions in the Napa Valley accompanied by expected increases in the use of ground water will probably cause significant reductions in the base flow of the Napa River and cause many shallow wells in the area to dry up. Sodium chloride ground water occurs near Calistoga and in the vicinity of Oakville and in some places is not suitable for irrigation. Model studies indicate that limited migration of sodium chloride water into intensively pumped parts of the aquifer probably will not be a serious problem.

California↗

Effects of the rate of releases from Sam Rayburn Reservoir on the aeration capacity of the Angelina River, eastern Texas

A three-phase study was conducted during July and August 1979 to determine the effects of varying release rates through the power-outlet works at Sam Rayburn Reservoir, eastern Texas, on aeration capacity of a 14-mile reach of the Angelina River below Sam Rayburn Dam. The dominant factors that affected the aeration capacity during the study time were time of travel and the dissolved-oxygen deficit of the releases. Aeration was low throughout the study but increased in response to increases in the dissolved-oxygen deficit and the duration of time that the releases were exposed to the atmosphere (time of travel). The average concentration of dissolved oxygen sustained by release of 8,800 cubic feet per second decreased from 5.0 milligrams per liter at a site near the power outlet to 4.8 milligrams per liter at a site about 14 miles downstream; the time of travel averaged about 8 hours. The average concentration of dissolved oxygen in flow sustained by releases of 2,200 cubic feet per second increased from 5.2 to 5.5 milligrams per liter; the time of travel averaged about 20 hours.

Texas↗

Investigation of artificial recharge of aquifers in Nebraska

Large withdrawals of ground water for irrigation are causing progressive declines of ground-water levels in some areas of Nebraska. An investigation was conducted to determine the technical feasibility of artificially recharging aquifers through wells and through surface spreading by means of impoundments, pits, and canals. Information gained from a literature search and from preliminary tests was used to design several artificial-recharge experiments. The experiments showed that large quantities of water can be recharged through wells and by surface spreading if conditions are favorable. In the well experiments, about 0.5 billion gallons of water from an aquifer recharged by the Platte River was transported 3 miles by pipeline and recharged through a well into a Pleistocene sand and gravel aquifer near Aurora where ground-water levels are declining. The recharge rate was about 730 gallons per minute during two tests of 6 and 8 months duration. The rise in ground-water levels due to recharge extended more than a mile from the recharge well in both tests. The pattern of ground-water-level buildup during the 8-month test was similar to that during the 6-month test. Two-thirds of the way through the test the rate of water-level buildup in the recharge well increased greatly because casing failure allowed a large amount of sediment to enter the well. Although the chemical quality of the recharge water was markedly different from that of the native aquifer water, no evidence of clogging due to chemical reaction was detected; also, there was no evidence of clogging due to air entrainment or bacterial growth. Evaluation of water-level changes in the recharge well and in observation wells during the 6-month test indicated some clogging of the aquifer in the immediate vicinity of the recharge well due to a small amount (0.04 milligram per liter) of fine sediment in the recharge water. Analysis of water-level buildup in the recharge well during the 6-month test indicated that recharge could have continued at a rate of about 700 gallons per minute for several years before rehabilitation of the recharge well would have been necessary. In surface-spreading experiments, the maximum sustained infiltration rates from a 24-foot-diameter ring infiltrometer set in loess at the well-recharge site near Aurora were about 0.5 foot per day during a 140day test. The recharge water caused water levels in a perched zone of saturation at depths between 36 and 38 feet to rise 15 feet, to within 21 feet of the surface, indicating that if the test had continued or if the impoundment area had been larger, the water level in the perched zone of saturation might have risen to the surface thereby reducing the infiltration rate. The maximum sustained infiltration rate from a similar experiment in the Sand Hills near Tryon was 11 feet per day. Perching layers also retarded downward infiltration and caused lateral movement of water in the subsurface at this site. Infiltration rates from re-use pits near the Aurora site ranged from 0.01 to 1.60 feet per day, indicating that the permeability of the subsurface material is extremely variable and that perching layers probably are absent in some areas. Flow measurements in an irrigation canal excavated in loess near Farwell indicate an infiltration rate of 0.36 foot per day from a 2.7mile reach.

Nebraska↗

Streamflow losses along the Balcones Fault Zone, Nueces River basin, Texas

An investigation was conducted to quantify and to determine distribution of streamflow losses and gains that occur during sustained flow conditions in the Balcones Fault Zone of the Nueces River basin. The streams studied include the West Nueces, Nueces, Dry Frio, Frio, and Sabinal Rivers, and Seco, Hondo, and Verde Creeks. Streamflow measurements made during the recession of storm flows identified direct recharge to outcrops of the Edwards aquifer and related limestones that ranged from as high as 393 cubic feet per second for the Dry Frio River to as low as 42 cubic feet per second for the Sabinal River. Recharge to outcrops of the Buda Limestone, Eagle Ford Shale, and Austin Group also eventually reaches the Edwards aquifer, and measurements identified losses to these formations ranging from as high as 174 cubic feet per second for the Frio River to near zero for Verde Creek. Statistical evaluations of historical daily flow records for the streams that have gaging stations upstream and downstream from the recharge zone provided mathematical relationships that expressed downstream flow in terms of other significant parameters. For each stream, flow entering the recharge zone is most significant in defining downstream flow; for some streams, antecedent flows at the upstream site and ground-water levels are also significantly related to downstream flow. The analyses also determined the discharges required upstream from the recharge zone to sustain flow downstream from that zone. These discharges ranged from 355 cubic feet per second for the combined Frio and Dry Frio Rivers to 33 cubic feet per second for the Nueces River. The entire flows of lesser magnitude are generally lost to recharge to the aquifer.

Texas↗

Hydrologic reconnaissance of the Unalakleet River basin, Alaska, 1982-83

The Unalakleet River, Alaska, from its headwaters to the confluence of the Chiroskey River has been designated as a wild river and is included in the National Wild and Scenic Rivers System. Yearly low flow, which occurs during the winter, is sustained by groundwater discharge; there are few lakes in the basin and the cold climate prevents winter runoff. The amount of winter streamflow was greatest in the lower parts of streams with the exception of the South River and was apparently proportional to the amount of unfrozen alluvium upstream from the measuring sites. Unit discharge in late winter ranged from nearly zero at the mouth of the South River to 0.24 cu ft/sec/sq mi in the Unalakleet River main stem below Tenmile River. Summer runoff at the time of the reconnaissance may have been slightly higher than normal owing to recent rains. Unit runoff ranged from a low of 1.0 cu ft/sec/sq mi at the South River, to a high value of 2.4 cu ft/sec/sq mi at the North Fork Unalakleet River. Flood marks were present in the basin well above streambank levels but suitable sections to measure the maximum evident flood by slope-area methods were not found. Flood peaks were calculated for the Unalakleet River and its tributaries using basin characteristics. Calculated unit runoff for the 50-year flood ranged from about 17 to 45 cu ft/sec/sq mi. Water quality was good throughout the basin, and an abundant and diversified community of benthic invertebrates was found in samples collected during the summer reconnaissance. Permafrost underlies most of the basin, but groundwater can be found in unfrozen alluvium in the stream valleys, most abundantly in the lower part of the main tributaries and along the main stem of the Unalakleet River. Groundwater sustains river flow through the winter; an estimate of its quantity can be found through low-flow measurements. Groundwater quality in the basin appears to be satisfactory for most uses. Currently, little groundwater is used within the basin. The water supply for Unalakleet is obtained from a well and gallery in a small valley north of the airport, outside the Unalakleet River basin. (Author 's abstract)

Water-Resources Investigations Report↗

Geochemistry of artificial-recharge tests in the Oakes aquifer near Oakes, southeastern North Dakota

As part of an artificial-recharge feasibility study, water from the James River was introduced into the Oakes aquifer of southeastern North Dakota by infiltration through a recharge basin. Chemical composition of water in the recharge basin and ground water from two separate flow paths beneath the basin was determined from samples taken during two artificial-recharge tests. Changes between recharge-basin water and ground water from the termination of the flow paths during the spring 1987 test included increases in alkalinity, calcium, sodium, and silica and decreases in pH and dissolved oxygen. Interpretation of processes modifying the chemical composition of recharge water was complicated by mixing of recharge water with pre-existing ground water within the Oakes aquifer. In the summer 1987 test, the recharge basin was lined with a decomposing organic mat. The purpose of the organic mat was to sustain large infiltration rates for a longer period of time and to evaluate the effect of a decomposing organic mat on water quality during sustained recharge-basin operation. Larger infiltration rates with the organic mat in place allowed recharge water to reach the termination of the flow paths prior to apparent mixing with pre-existing ground water for a period of as much as approximately 405 hours of recharge-basin operation. Changes between recharge-basin water and ground water from the termination of the flow paths during the summer 1987 organic-mat test included increases in alkalinity, calcium, and silica and decreases in pH, dissolved oxygen, and total organic carbon. Detected changes between recharge-basin water and ground water from the termination of the flow paths were interpreted using a mass-balance geochemical model. Chemical changes of at least 2 milligrams per liter were modeled in terms of reactions, including those due to respiration of micro-organisms, dissolution of carbon dioxide, possible production of organic acids, dissolution of amorphous silica, cation exchange, and dissolution of carbonate minerals. Generation of organic acids within the decomposing organic mat may cause dissolution of dolomite in the subsurface.

Water-Resources Investigations Report↗

Water resources of Indiana County, Pennsylvania

Indiana County, west-central Pennsylvania, is a major producer of coal and natural gas. Water managers and residents are concerned about the effects of mining and natural gas exploration on the surface- and ground-water resources of the county. This study assesses the quality and quantity of water in Indiana County. Ground- and surface-water sources are used for public supplies that serve 61 percent of the total population of the county. The remaining 39 percent of the population live in rural areas and rely on cisterns and wells and springs that tap shallow aquifers. Most of the county is underlain by rocks of Middle to Upper Pennsylvanian age. From oldest to youngest, they are the Allegheny Group, the Glenshaw Formation, the Casselman Formation, and the Monongahela Group. Almost all the coals mined are in the Allegheny Group and the Monongahela Group. Ground water in Indiana County flows through fractures in the rock. The size and extent of the fractures, which are controlled by lithology, topography, and structure, determine the sustained yield of wells. Topography has a significant control over the yields of wells sited in the Allegheny Group. Properly sited wells in the Glenshaw Formation may have yields adequate for municipal, commercial, or industrial uses. The Casselman Formation yields adequate amounts of water for domestic use. Yield of the Monongahela Group is small, and the water may not be of suitable quality for most uses. Yields of hilltop wells may be marginal, but valley wells may yield sufficient amounts for large-volume users. Data on the other rock units are sparse to nonexistent. Few wells in the county yield more than 40 gallons per minute. Most of the wells that do are in valleys where alluvial deposits are extensive enough to be mapable. Short-term water-level fluctuations are variable from well to well. Seasonal water-level fluctuations are controlled by time of year and amount of precipitation. The quality of water from the Casselman Formation, Glenshaw Formation, and Allegheny Group tends to be hard and may have concentrations of iron and manganese that exceed the U.S. Environmental Protection Agency Secondary Maximum Contaminant Levels of 0.3 milligrams per liter and 0.05 milligrams per liter, respectively. Ground water from the Glenshaw Formation is less mineralized than ground water from the Allegheny Group. Concentrations of minerals in water from the Casselman Formation are between those in water from the Glenshaw Formation and the Allegheny Group. Water from wells on hilltops has lower concentrations of dissolved solids than water from wells on hillsides. Water from valley wells is the most mineralized. Nearly half the springs tested yield water that is low in pH and dissolved solids; this combination makes the water chemically aggressive. The 7-day, 10-year low-flow frequencies for 26 unregulated surface-water sites ranged from 0.0 to 0.19 cubic feet per second per square mile. The presence of coal mines and variations in precipitation were probably the principal factors affecting flow duration on Blacklick Creek (site 28) during 1953-88. Sustained base flows of regulated streams such as Blacklick Creek generally were larger than those of unregulated streams as a result of low-flow augmentation. The annual water loss in streamflow as a result of evapotranspiration, diversion, seepage to mines, and seepage to the ground-water system was determined at four sites (sites 8, 9, 17, and 28) and ranged from 35 to 53 percent. The highest concentrations of dissolved solids, iron, manganese, aluminum, zinc, and sulfate were measured mostly in streams in central and southern Indiana County, where active and abandoned coal mines are the most numerous. Streamflow was measured during low flow in two small basins; one basin almost completely deep mined (Cherry Run) and one basin unmined (South Branch Plum Creek). The measurements showed a con

Pennsylvania↗

Low-flow characteristics and profiles for selected streams in the Roanoke River basin, North Carolina

An understanding of the magnitude and frequency of low-flow discharges is an important part of protecting surface-water resources and planning for municipal and industrial economic expansion. Low-flow characteristics are summarized for 22 continuous-record gaging stations in North Carolina (19 sites) and Virginia (3 sites) and 60 partial-record gaging stations in the North Carolina Roanoke River Basin. Records of discharge collected through the 1994 water year are used. Flow characteristics included in the summary are (1) average annual unit flow, (2) 7Q10 low-flow discharge, the minimum average discharge for a 7 consecutive-day period occurring, on average, once in 10 years; (3) 30Q2 low-flow discharge; (4) W7Q10 low-flow discharge, similar to 7Q10 discharge except that flow during November through March only is considered; and (5) 7Q2 low-flow discharge. The potential for sustaining base flows is moderate to high in the western part of the basin as well as in the eastern and western fringes of the Piedmont and Coastal Plain physiographic provinces, respectively. Areas of low potential for sustaining base flow exist in the central part of the basin (between eastern Caswell County and western Warren County), where soils have low infiltration rates, and in lower regions of the Coastal Plain, where small streams tend to have zero flow during prolonged drought. Drainage area and low-flow discharge profiles are presented for 10 streams in the Roanoke River Basin in North Carolina and reflect a wide range in basin size, characteristics, and streamflow conditions. The selected streams are Town Fork Creek, Hogans Creek, Mayo River, Buffalo Creek, Smith River, Country Line Creek, Dan River, Marlowe Creek, Hyco River, and Roanoke River. The drainage-area profiles show the increases in drainage areas as streams travel their course in the basin. At the mouths of streams profiled, the drainage areas range from 22 miles to about 9,700 miles. Low-flow discharges for each stream include 7Q10, 30Q2, W7Q10, and 7Q2 discharges in a continuous profile with contributions from major tributaries included.

North Carolina↗

Geology and ground water in the Platte-Republican Rivers watershed and the Little Blue River basin above Angus, Nebraska, with a section on chemical quality of the ground water

This report describes an area of about 7,300 square miles in south-central Nebraska. Approximately one-fourth of the area, largely at its east end, consists of an undissected southeastward-sloping upland plain and is almost wholly irrigable; the remainder is in various stages of dissection and only parts of it are suitable for irrigation. Although some of the deeper lying bedrock formations are potential sources of water supply, they are not likely to be tapped in the near future because abundant supplies are available at shallower depth from semiconsolidated and unconsolidated deposits. The Ogallala formation of Tertiary (Pliocene) age consists of gravel, sand, silt, and volcanic ash, some layers of which are partly cemented. It was deposited by eastward-flowing streams, which formed a constructional plain above a surface into which the streams had previously eroded broad valleys. In turn, valleys were cut into the surface of the Ogallala before the overlying deposits of gravel, sand, silt, and clay of Quaternary (Pleistocene) age were laid down, also forming a constructional plain. During Recent time, streams have dissected the older deposits and have deposited thin alluvium in their valleys; also, several parts of the area have become mantled by wind-deposited sand. Because during Tertiary and Quaternary time the area repeatedly was the site of deposition and erosion, the thickness of all the stratigraphic units differs markedly from place to place. In general, however, the Ogallala formation thins eastward and in the central and eastern parts of the area is overlain by the eastward-thickening deposits of Pleistocene age. The maximum thickness of the Ogallala formation is about 500 feet, and the maximum thickness of the Pleistocene deposits is a little more than 300 feet. Each thins to a featheredge and is completely absent in parts of the area. The water-bearing part of the combined Tertiary and Pleistocene deposits is considered to be a single zone of saturation because the ground water, as it percolates southeastward beneath the area, moves out of the Tertiary and into the Quaternary deposits without apparent hindrance. The water that enters the area as underflow from the west is augmented within the area by water that infiltrates from the land surface. The principal sources of irrigating water are precipitation, seepage from canals and reservoirs, and applied irrigation water. Except for the water withdrawn through wells or discharged by natural processes where valleys have been cut into the zone of saturation, ground water leaves the area as underflow into the Platte River valley on the north, the Blue River drainage basin on the east, or the Republican River valley on the south. Part of the water used for irrigation and watering livestock and all the water used in rural and urban homes, in public buildings, and for industrial purposes is obtained from wells, To date (1952) there is no indication that the supply of ground water is being depleted faster than it is being replenished; instead, studies indicate that greater quantities can be withdrawn without causing an excessive decline of the water table. An increase of ground-water withdrawals to a sustainable maximum, however, will be possible only if the points of withdrawal are scattered fairly uniformly. It is estimated that annual withdrawals per township should not exceed 2,100 acre-feet where infiltrating precipitation is the only source of recharge, or 3,000 acre-feet where other sources of recharge are significant. Although perennial withdrawals of this amount could be sustained indefinitely, they would cause some lowering of the water table and eventually a decrease in the amount of water discharged from the area by natural means. The ground water is of the calcium bicarbonate type. In much of the area it is hard or very hard, and in places it contains excessive amounts of iron. In all other respects the water is chemically suitable for domesti

Nebraska↗

Swatara Creek basin of southeastern Pennsylvania: An evaluation of its hydrologic system

Local concentrations of population in the Swatara Creek basin of Pennsylvania find it necessary to store, transport, and treat water because local supplies are either deficient or have been contaminated by disposal of wastes in upstream areas. Water in the basin is available for the deficient areas and for dilution of the coal-mine drainage in the northern parts and the sewage wastes in the southern parts. Swatara Creek drains 576 square miles just east of Harrisburg, Pa., and is the largest tributary to the Susquehanna River from the north side below Harrisburg. It rises in the southern Pocono Mountains and flows southwestward across the Lebanon Plateau. On an average day Swatara Creek discharges more than 630 million gallons into the Susquehanna River at Middletown, Pa. In a year this amounts to about 23 inches of water over the entire basin and is the residual from an average annual precipitation of 45.5 inches. During an average year the flow in Swatara Creek from the upper third of the basin above Harper Tavern is always greater than 1,300 mgd (million gallons per day) for at least 15 days and is always greater than 25 mgd for at least 350 days. The daily streamflow from the basin averages 1.1 mgd per sq mi, but yields from different areas range from 0.97 to 1.22 mgd per sq mi. These variations are caused chiefly by differences in precipitation and land cover. The area of lowest yield is in the valleys west of Tremont, and the highest yields are in the Upper and Lower Little Swatara Creek subbasins. At high and medium stages the chemical character of the water in the streams is suitable for public and private supplies. At lower stages, defending on the areas and the amounts of contamination by coal-mine drainage and sewage pollution, the natural flow may require some treatment. At low stages the chemical characteristics of the natural flow not affected by man is almost identical with that of the ground water in the area drained by the stream. In general, the total dissolved solids range from about 25 to 400 parts per million and the hardness is as much as about 300 parts per million. The ground-water increment to the base flow of Swatara Creek averages about 240 mgd, or about 8.8 inches annually, for the basin. Generally, ground-water supplies in amounts of less than 0.5 mgd can be developed south of Blue Mountain. Supplies of several million gallons per day have been developed for industrial use from the permeable limestones in the south-central part of the basin. More intensive investigation in other parts of the basin would indicate areas where supplies of more than 0.5 mgd could be developed from properly spaced wells. The chemical character of water from wells depends largely on the host rock. In highly soluble rocks water contains large amount of dissolved solids; in more resistant rocks concentrations are lower. The chemical character of unpolluted ground water generally reflects the composition of the more readily soluble minerals in the local geologic environment. Areas contaminated by septic- tank effluent may have above normal amounts of nitrate and detergent products. Except where polluted, most ground water is suitable for public and industrial uses without extensive treatment. Sites for storage of surface water exist in the part of the basin lying in the valley and ridge area. As much as 30 to 40 percent of the annual flow could be impounded for release as low-flow augmentation for dilution of mine drainage and other wastes in the basin. Low sediment yields of supplying drainage areas would ensure a long life expectancy of reservoirs at these sites. Overbank flooding of the main stem of the Swatara Creek and its tributaries has occurred many times in the past. However, it has not been a hazard because urban development has not encroached on the flood plain. An inundation map of the August 1933 flood provides a basis that urban planners may use to avoid future damage. As water in the Swatara Creek moves downstream to the Susquehanna River, the flow is influenced consecutively by a large annual rainfall on the northern valley and ridge area, the wastes of surface and subsurface coal-mining activities, and less annual rainfall on the part of the basin lying in the Lebanon Plateau area; the flow is supplemented and further influenced by many tributaries and by the industrial and domestic wastes that are carried by these secondary streams. The annual precipitation ranges from 52 inches at the east edge and 49 inches at the west edge of the mountainous part of the basin to about 41 inches at the southwestern part at Middletown. The rainfall generally is adequate during the growing season to mature the crops. The mean annual temperature at Lebanon is about 52°F, and the growing season is about 180 days. In this report the basin has been divided into eight hydrologic zones, leased on runoff, natural use of water, and chemical character of water. Four zones lie in the valley and ridge area, three lie in the Lebanon Plateau area, and one lies in the highland along the southeastern basin boundary. In each of the zones the hydrologic characteristics are virtually the same, but they may be completely different from those in adjacent zones. The boundaries of the zones generally coincide with boundaries between geologic formations, and the areas in each zone include rocks of similar influence on water. Streams in zone 4 at the northeast edge of the plateau have the highest average surface runoff from 1.2 to 1.1 mgd per sq mi whereas those in zone 2 at the northwest edge of the valley and ridge area have the lowest, about 1.0 mgd. Streams in zone 8, along the southeast edge of the basin, have the largest sustained low-flow yield, about 0.26 to 0.19 mgd per sq mi; those in zone 5 overlying the Martinsburg Shale east of Harrisburg have the smallest sustained low-flow yields, 0.03 to 0.01 mgd. Streams in the limestone area of zone 7 have the greatest range in low-flow yields in any one zone from 0.60 to 0 mgd per sq mi. Low-flow yields in zones 1 through 4 range from 0.13 to 0.03 mgd per sq mi. Surface flows from zones 1 and 2 are generally acidic and contain high concentrations of sulfate, iron, and total dissolved solids especially where contaminated with mine wastes. Surface flows from zones 3 and 4 are dilute, slightly alkaline, and suitable for public water supplies. Surface flows from zones 5, 6, and 7 are alkaline and contain moderate concentrations of dissolved solids with waters of highest hardness occurring in zone 7. Surface flows from zone 8 are dilute to moderately mineralized and are relatively high in silica concentration. Nitrate concentrations are high in surf Fee flows below sewage outfalls and in ground water contaminated by septic tank effluent and industrial wastes. Average annual sediment yields of 550 to 650 tons per square mile are characteristic of zones 1 and 2 where strip mining has destroyed the forest cover and coal culm is carried into the streams. From agricultural lands on the Martinsburg Shale in zones 5 and 6, annual sediment yields range from 300 to 350 tons per square mile; but from agricultural lands on the siliceous rocks in zone 8 and zones 3 and 4 in the valley and ridge area, the sediment yield ranges from 200 to 250 tons annually per square mile. Lowest annual sediment yields in the basin are in the forested areas of siliceous rocks in zones 2, 3, 4, and 5, and in the sinkhole topography of the limestones in zone 7 where the yield ranges from 30 to 35 tons and 50 to 60 tons per square mile, respectively. The amount of ground water that can be developed in the basin is dependent on the ability of the underlying rocks to yield water to wells. More than 300 gpm (gallons per minute) can be obtained from wells in alluvial materials in the valley bottoms and in some of the limestones where large solution channels and fractures are penetrated by the wells. From 50 to 300 gpm can be obtained from wells in loosely cemented sandstones and in fractured limestones. From 10 to 50 gpm can be developed from wells in the shales and harder sandstones. The most dense rocks will yield from 1 to 10 gpm from fractures and crevices. Most wells yield water from the upper 350 feet of the formation, for this part contains the most fractures or solution channels. Studies show that the velocity at which a contaminant will move downstream in the basin is related to the discharge of the stream at the time. At a stream discharge of about 400 mgd at Pine Grove, a contaminant in Swatara Creek would require about 40 hours to move from Pine Grove to Middletown. As a result of dispersion and dilution, the maximum concentration of the contaminant at Middletown would be less than 20 percent the concentration at Pine Grove under these conditions. An evaluation of the availability of water in the basin indicates that about I,239 mgd enters as precipitation, 630 mgd leaves as streamflow, 580 mgd is evaporated and transpired, and 56 mgd is diverted for use by man. Not all the diversions for man's use are lost to the basin, as about 27 mgd is returned as sewage for reuse. About one-fourth of the waste water is returned to the ground and the remainder to stream drainageways. Of that diverted by man, 11.6 mgd is used for public supply and 44.4 mgd for industrial and private supplies. Diversions of streamflow furnish 86 percent of the public supply and 27 percent of the industrial supply, and ground-water sources yield the remainder. Municipal and private sewage treatment plants are upgrading the waste water in many places, but no provisions are being made for treatment other than natural dilution and assimilation for the 15 mgd of coal-nine drainage in the northern part of the basin. Technology for economic treatment of mine water is not available at this time, although research in this field is being done. Urbanization eastward from Harrisburg and around Lebanon has increased the population density of the basin. Densities of 500 people per square mile and water use exceeding 2.0 mgd per sq mi can be expected in the future. By the year 2000 the population of the basin may increase 60 percent; and if the per capita rate of use increases 0.5 percent per year the domestic requirements for water will be about two times the present use, or 23 mgd. Similarly, if the present 1:4 ratio of domestic use to industrial use of water continues, at least 89 mgd will be needed for industry in the future. Although an increase to twice the present use of water can be foreseen, or 112 mgd, water for the dilution and assimilation of wastes from treatment systems are not included. Providing water for dilution of wastes from treatment plants has not been a problem, but in the future the amounts needed for this purpose will be greater as the population increases. As water becomes more valuable, treatment of sewage wastes to reduce the biochemical-oxygen-demand load by at least 80 to 90 percent will be necessary to conserve water for more productive uses. As much as 100 mgd may be needed for waste dilution in the basin by year 2000. The present trends in suburban and light industrial development will probably persist in the basin. Problems arising through changes in economic value of water, conflicts in use, and alternatives in development are typical of those confronting the manager of a water-resource system.

Pennsylvania↗

Water resources of the New Jersey part of the Ramapo River basin

The Ramapo River, a major stream in the Passaic River basin, drains an area of 161 square miles, 70 percent of which is in Orange and Rockland Counties, N.Y., and 30 percent is in Bergen and Passaic Counties, N.J. This report describes the hydrology of the New Jersey part of the basin and evaluates the feasibility of developing large ground-water supplies from the stratified drift in the Ramapo River valley by inducing recharge to the aquifer from the river. The ground water and surface water of the basin are considered as a single resource because the development of either ground water or surface water affects the availability of the other. Precambrian gneiss, sparsely mantled with Pleistocene glacial drift, underlies the basin west of the Ramapo River in New Jersey. To the east, bedrock consists of the Watchung Basalt and of shale, sandstone, and conglomerate of the Brunswick Formation of Triassic age. Glacial drift occurs nearly everywhere in the eastern part of the basin, and deposits of stratified drift more than 100 feet thick occur in the Ramapo valley. Average annual runoff at Pompton Lakes accounts for 25 inches of the 45 inches of annual precipitation in the New Jersey part of the basin, and the remaining 20 inches is accounted for by evapotranspiration. Streamflow is highly variable--particularly in the area underlain by gneissic rocks-because of the low storage capacity of the rocks and the rough topography. Many of the small tributaries go dry during extended periods of no precipitation. Small domestic supplies of ground water can be obtained nearly everywhere, but the Brunswick Formation is the only consolidated-rock aquifer in the basin that can be depended upon to yield 100-200 gallons per minute to wells. Supplies of more than 1,000 gallons per minute are available from wells tapping the stratified drift in the Ramapo valley. The drift supplies 75 percent of the ground water pumped for public supply in the basin. Sustained ground-water yield in upland areas, based on stream base-flow recession, is estimated to be 200,000-300,000 gallons per day per square mile for the drift-covered Brunswick Formation and about 100,000-200,000 gallons per day per square mile for the gneiss and basalt. Potential sustained yield of the stratified drift in the valley depends on the availability of the streamflow and on the induced rate of infiltration. Pumping from the stratified drift results in a reduction in streamflow, which may be undesirable, mainly because of prior downstream water rights. On the basis of the storage available in the stratified drift and an analysis of daily flow during the drought period of October 1964 to September 1967 at Pompton Lakes, 20-25 million gallons per day of Ramapo River water are available for development after existing downstream water requirements are supplied. However, some low-flow augmentation will be. necessary to insure downstream rights. Rates of infiltration computed from seepage losses observed near Mahwah indicate that at least 11 million gallons per day, on an average basis, can be infiltrated from the river by the pumping of wells tapping the stratified drift. The use of recharge pits and spreading areas would increase the rate of infiltration. Losses from the Ramapo River could be minimized by returning treated sewage effluent directly to the river or, preferably, by recharging the stratified-drift aquifer with the treated effluent. Ground-water quality and surface-water quality at times of low-flow vary according to the type of rock from which the water is obtained. Water from the gneiss is low in dissolved solids--less than 127 mg/l (milligrams per liter)--and soft to moderately hard--less than 94 rag/l. Water from the Brunswick Formation is more mineralized--total dissolved-solids content is as much as 278 mg/1 and hardness as much as 188 mg/1. Water from the stratified drift is generally intermediate in quality--that is, total dissolved-solids content is as

Water Supply Paper↗

Appraisal of ground water for irrigation in the Little Falls area, Morrison County, Minnesota

Anticipated irrigation on sandy soils has prompted evaluation of ground-water supply potential in the Little Falls area. Geologic conditions cause ground-water availability to vary widely in the area. The largest and most readily available groundwater source is the glacial outwash sand and gravel from which the soils were derived. Test augering shows that the saturated surficial outwash is as much as 50-100 feet thick in the area where the outwash fills a probable former meltwater channel and that it is also this thick in smaller areas elsewhere. Transmissivity of the thicker parts of the aquifer approaches or exceeds 100,000 gallons per day per foot, and probable well yields should exceed 1,000 gallons per minute. In about two-thirds of the study area, a saturated thickness of less than 40 feet generally limits well yields to less than 300 gallons per minute. Recharge to the surficial aquifer is obtained primarily from precipitation. Most discharge occurs as evapotranspiration, base flow to the Mississippi River, and base flow to other streams and to lakes. Possible future response to pumping was studied through electric analog analyses by stressing the modeled aquifer system in accordance with areal variations in expected well yields. The model interpretation indicates most of the sustained pumpage would be obtained from intercepted base flow and evapotranspiration. Simulated withdrawals totaling 18,000 acre-feet of water per year for 10 years resulted in little adverse effect on the aquifer system. Simulated larger withdrawals, assumed to represent denser well spacing, caused greater depletion of aquifer storage, streamflow, and lake volumes, excessively so in some areas. Results of model analyses provide a guide for ground-water development by identifying the capability of all parts of the aquifer system to support sustained pumping for irrigation.

Minnesota↗

Evaluation of a fine sediment removal tool in spring-fed and snowmelt driven streams

The accumulation of fine-grained sediments impairs the structure and function of streams, so removing fine sediments may be required to achieve restoration objectives. There has been little work on methods of removing excess sediment or on the efficacy of the methods. We used a 4-year before-after-control-impact design in southeastern Idaho streams to test a fine sediment removal system (FSRS) manufactured by Streamside Environmental LLC. The FSRS agitates fine sediment in the substrate with clean pump water and then vacuums the sediment out of the stream with a second pump. Our objectives were: 1) to test if the FSRS can selectively remove fine sediment; 2) to monitor the bio-physical responses in FSRS treated and downstream waters; and 3) to compare the bio-physical responses to the FSRS in spring-fed and snowmelt driven stream reaches. The FSRS removed ~ 14 metric tons of sediment from the two treated reaches. More than 90% of this sediment was < 2 mm, indicating that the FSRS selected for fine sediment in both stream types. Sustained effects of removing this sediment were confined to substrate improvements in treated reaches. Embeddedness in the spring-fed reach decreased and subsurface grain size in spring-fed and snowmelt driven reaches increased. We did not detect any sustained invertebrate or fish responses in treated reaches or any detrimental bio-physical responses in downstream waters. These results indicate that the FSRS reduced fine sediment levels but sediment removal did not reverse the impacts of sediment accumulation to stream biota within our monitoring time frame.

Ecological Restoration↗

Lava fountain jet noise during the 2018 eruption of fissure 8 of Kīlauea volcano

Real-time monitoring is crucial to assess hazards and mitigate risks of sustained volcanic eruptions that last hours to months or more. Sustained eruptions have been shown to produce a low frequency (infrasonic) form of jet noise. We analyze the lava fountaining at fissure 8 during the 2018 Lower East Rift Zone eruption of Kīlauea volcano, Hawaii, and connect changes in fountain properties with recorded infrasound signals from an array about 500 m from the fountain using jet noise scaling laws and visual imagery. Video footage from the eruption reveals a change in lava fountain dynamics from a tall, distinct fountain at the beginning of June to a low fountain with a turbulent, out-pouring lava pond surrounded by a tephra cone by mid-June. During mid-June, the sound pressure level reaches a maximum, and peak frequency drops. We develop a model that uses jet noise scaling relationships to estimate changes in volcanic jet diameter and jet velocity from infrasound sound pressure levels and peak frequencies. The results of this model indicate a decrease in velocity in mid-June which coincides with the decrease in fountain height. Furthermore, the model results suggest an increase in jet diameter, which can be explained by the larger width of the fountain that resembles a turbulent lava pond compared to the distinct fountain at the beginning of June. The agreement between the infrasound-derived and visually observed changes in fountain dynamics suggests that jet noise scaling relationships can be used to monitor lava fountain dynamics using infrasound recordings.

Hawaii↗

Advancing marine biological observations and data requirements of the complementary Essential Ocean Variables (EOVs) and Essential Biodiversity Variables (EBVs) Frameworks

Measurements of the status and trends of key indicators for the ocean and marine life are required to inform policy and management in the context of growing human uses of marine resources, coastal development, and climate change. Two synergistic efforts identify specific priority variables for monitoring: Essential Ocean Variables (EOVs) through the Global Ocean Observing System (GOOS), and Essential Biodiversity Variables (EBVs) from the Group on Earth Observations Biodiversity Observation Network (GEO BON). Both systems support reporting against internationally agreed conventions and treaties. GOOS, established under the auspices of the Intergovernmental Oceanographic Commission (IOC), plays a leading role in coordinating global monitoring of the ocean and in the definition of EOVs. GEO BON is a global biodiversity observation network that coordinates observations to enhance management of the world’s biodiversity and promote both the awareness and accounting of ecosystem services. Convergence and agreement between these two efforts are required to streamline existing and new marine observation programs to advance scientific knowledge effectively and to support the sustainable use and management of ocean spaces and resources. In this context, the Marine Biodiversity Observation Network (MBON), a thematic component of GEO BON, is collaborating with GOOS, the Ocean Biogeographic Information System (OBIS), and the Integrated Marine Biosphere Research (IMBeR) project to ensure that EBVs and EOVs are complementary, representing alternative uses of a common set of scientific measurements. This work is informed by the Joint Technical Commission for Oceanography and Marine Meteorology (JCOMM), an intergovernmental body of technical experts that helps international coordination on best practices for observing, data management and services, combined with capacity development expertise. Characterizing biodiversity and understanding its drivers will require incorporation of observations from traditional and molecular taxonomy, animal tagging and tracking efforts, ocean biogeochemistry, and ocean observatory initiatives including deep ocean and seafloor. The partnership between large-scale ocean observing and product distribution initiatives (MBON, OBIS, JCOMM, and GOOS) is an expedited, effective way to support international policy-level assessments (e.g., the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services or IPBES), along with the implementation of international development goals (e.g., the United Nations Sustainable Development Goals).

Frontiers in Marine Science↗