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Research about Clallam County, Washington

Source-linked reports with geographic coverage including Clallam County, Washington.

9 recordsLinked to original sources
USGS2008

Bank topography, bathymetry, and current velocity of the lower Elwha River, Clallam County, Washington, May 2006

The removal of two dams from the mainstem of the Elwha River is expected to cause a broad range of changes to the river and nearby coastal ecosystem. The U.S. Geological Survey has documented aspects of the condition of the river to allow analysis of ecological responses to dam removal. This report documents the bank topography, river bathymetry, and current velocity data collected along the lower 0.5 kilometer of the Elwha River, May 15-17, 2006. This information supplements nearshore and beach surveys done in 2006 as part of the U.S. Geological Survey Coastal Habitats in Puget Sound program near the Elwha River delta in the Strait of Juan de Fuca, Washington.

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USGS2002

Surface water-ground water interactions along the lower Dungeness River and vertical hydraulic conductivity of streambed sediments, Clallam County, Washington, September 1999-July 2001

The Dungeness River emerges from the Olympic Mountains and flows generally north toward the Strait of Juan De Fuca, crossing the broad, fertile alluvial fan of the Sequim-Dungeness peninsula in northeastern Clallam County, Washington. Increasing competition for the peninsula's ground-water resources, changing water-use patterns, and recent requirements to maintain minimum in-stream flows to enhance endangered salmon and trout populations have severely strained the peninsula's water resources and necessitated a better understanding of the interaction between surface water and groundwater. Three methods were used to characterize the interchange between surface water and groundwater along the lower 11.8 miles of the Dungeness River corridor between September 1999 and July 2001. In-stream mini-piezometers were used to measure vertical hydraulic gradients between the river and the water-table aquifer at 27 points along the river and helped to define the distribution of gaining and losing stream reaches. Seepage runs were used to quantify the net volume of water exchanged between the river and ground water within each of five river reaches, termed 'seepage reaches.' Continuous water-level and water-temperature monitoring at two off-stream well transects provided data on near-river horizontal hydraulic gradients and temporal patterns of water exchange for a representative gaining stream reach and a representative losing stream reach. Vertical hydraulic gradients in the mini-piezometers generally were negative between river miles 11.8 and 3.6, indicating loss of water from the river to ground water. Gradients decreased in the downstream direction from an average of -0.86 at river mile 10.3 to -0.23 at river mile 3.7. Small positive gradients (+0.01 to +0.02) indicating ground-water discharge occurred in three localized reaches below river mile 3.7. Data from the seepage runs and off-stream transect wells supported and were generally consistent with the mini-piezometer findings. An exception occurred between river miles 8.1 and 5.5 where seepage results showed a small gain and the mini-piezometers showed negative gradients. Vertical hydraulic conductivity of riverbed sediments was estimated using hydraulic gradients measured with the mini-piezometers and estimated seepage fluxes. The resulting conductivity values ranged from an average of 1 to 29 feet per day and are similar to values reported for similar river environments elsewhere. The results of this study will be used to calibrate a transient, three-dimensional ground-water flow model of the Sequim-Dungeness peninsula. The model will be used to assess the potential effects on ground-water levels and river flows that result from future water use and land-use changes on the peninsula.

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USGS1999

Hydrogeologic assessment of the Sequim-Dungeness area, Clallam County, Washington

The Sequim-Dungeness area covers 116 square miles (mi 2 ) on the northern part of the Olympic Peninsula in northwestern Washington. The central part of this area (74 mi 2 ) was designated as a primary study area. During the past two decades, the population has rapidly increased, land use has changed from mostly agricultural to residential, and salmon populations in the Dungeness River have appreciably declined. The increasing competition for water combined with a close relation between ground water, the Dungeness River, and an extensive irrigation system has created a need for a better understanding of ground water and the relation between ground water and surface water in the study area. The Sequim-Dungeness area is underlain by as much as 2,000 feet of unconsolidated Quaternary deposits that are mostly of glacial origin. Interpretation of 10 hydrogeologic cross sections and lithologic logs of about 600 wells led to the delineation of three aquifers, two confining beds, and a lower unit of undifferentiated deposits. A bedrock unit at the bottom is considered the base of the ground-water system. Ground water in the study area is recharged from infiltration and percolation of precipitaton, percolation of unconsumed irrigation water, leakage from irrigation ditches, subsurface inflow through the southern study-area boundary, and leakage from streams. Average annual recharge for the study period (December 1995 to September 1997) was estimated to be 17.7 inches (in.) ( 151 cubic feet per second (ft 3 /s)). The distribution of recharge was 8.6 in. (74 ft3fs) from precipitation, 2.7 in. (23 ft 3 /s) from subsurface inflow, 3.1 in. (26 ft 3 /s) from irrigation, and 3.3 in. (28 ft 3 /s) from leakage from the Dungeness River. The 8.6 in. of recharge from precipitation is much higher than would be expected in an average year because average annual precipitation during the study period was about 28 in., which is 1.35 times higher than long-term average annual precipitation. The long-term average annual recharge from precipitation was estimated to be 5.4 in. (48 ft 3 /s). Ground water discharges as subsurface flow to saltwater bodies, flow to streams, flow to springs, and as withdrawals from wells. Subsurface flow to saltwater bodies and flow to springs were not estimated in this study. Estimated average annual discharge was 3.2 inches (in.) (27 ft 3 /s)) to the Dungeness River and 4.6 in. (39 ft 3 /s) to other streams in the study area. Gross withdrawals from wells in 1996 were estimated to be 1.0 in. (8.4 ft 3 /s). There was a small but statistically significant increase in nitrate concentrations in ground water from 1980 to 1996. Median concentrations in the primary study area were 0.37 milligrams per liter (mg/L) in 1980 and 0.46 mg/L in 1996. The areal pattern of elevated nitrate concentrations has not changed appreciably during the past 15 years. Elevated concentrations were found in a large area east of the Dungeness River and at scattered locations west of the Dungeness River. About 543,200 pounds of nitrogen are estimated to enter the ground-water system in the primary study area each year. Four sources account for about 85 percent of the nitrogen; residential fertilizers, septic systems, mineralization of soil organic matter, and agricultural fertilizers .. It appears that the four major sources are approximately equivalent in amounts of nitrogen. Concentrations of nitrate in the shallow aquifer were significantly higher under residential areas than under natural grasslands or forests. Median nitrate concentrations were 1.3 mg/L under residential areas, 0.55 mg/L under agricultural areas, and 0.12 mg/L under natural grasslands or forests.

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USGS1986

Water resources of Clallam County, Washington: Phase I report

An inventory of the water resources of Clallam County, Washington, showed that sufficient water is available to supply all present demands. Domestic water supplies can be obtained from wells drilled 100 ft or less into glacial and alluvial deposits; in areas underlain by bedrock, wells more than 100 ft deep can generally supply one home per well. Surface water is abundant, and is the source for most public water systems. Extreme low flows were observed only in small drainage basins in bedrock in the mountainous interior and along parts of the coastline in the Strait of Juan de Fuca. The quality of ground and surface waters is generally excellent. In coastal areas, some wells may yield water with large concentrations of chloride and dissolved solids. A quarter of the wells tested had excessive concentrations of iron and (or) manganese. High values of turbidity, color, and coliform bacteria are widespread surface water problems, but standard filtering and chlorination treatment make the water suitable for public supplies. High concentrations of coliform bacteria apparently originate naturally in soils. High ammonia concentration observed at one site is probably caused by sewage disposal practices. (USGS)

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USGS1983

Impact of changes in land use on the ground-water system in the Sequim-Dungeness Peninsula, Clallam County, Washington

A digital-computer model was developed to simulate three-dimensional ground-water flow in aquifers underlying the Sequim-Dungeness peninsula, Clallam County, Washington. Analysis using the model shows that leakage from irrigation ditches is the area 's most important source of ground-water recharge. Termination of the irrigation system would lead to lower heads throughout the ground-water system. After 10-20 years of no irrigation, the water-table aquifer would have average drawdowns of about 20 feet and some areas would become completely unsaturated. Several hundred wells could be in danger of going dry. If irrigation were terminated, leakage from the Dungeness River would become the major source of ground-water recharge. As of June 1980, ground-water quality has apparently not been affected in the study area by the use of on-site domestic sewage-disposal systems. The median nitrate-plus-nitrite (as N) concentration in the water-table aquifer was 0.25 milligrams per liter, and the maximum concentration was 2.5 milligrams per liter.

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USGS1979

Flood elevations for the Sooes River at proposed fish hatchery, Clallam County, Washington; a surface-water site study

Water-surface elevations were derived for various combinations of selected river discharges and tide elevations along a reach of the Sooes River 3 miles upstream from the mouth at the site of a proposed fish hatchery in Clallam County, Washington. Flood-frequency analyses determined river discharges having exceedence probabilities of 1, 2, 4, 10 and 20 percent (100-, 50-, 25-, 10-, and 5-year recurrence intervals) and tide elevations having exceedence probabilities of 1 and 50 percent (100- and 2-year recurrence intervals). A relationship was developed for determining river water-surface elevation for different combinations of river discharge and tide elevations. Seven different combinations of river flood-plain conditions that may be expected to occur during and after construction were simulated and water-surface elevations determined by use of the step-backwater computer program.

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USGS1978

Preferred and observed conditions for sockeye salmon in Ozette Lake and its tributaries, Clallam County, Washington

Ozette River and Ozette Lake and its tributaries in Washington have many of the water-quality and stream-hydraulic characteristics that are generally supportive of good sockeye salmon production. Ozette Lake is a large, deep lake and a natural rearing area and for young sockeye. In the summer of 1976 water temperatures preferred for the growth of young sockeye (45-68 degrees Fahrenheit) occurred between about 200 feet of depth and the water surface, or generally in the zone of steep temperature gradient. Dissolved-oxygen concentrations in excess of 8.0 milligrams per liter at all depths throughout the year provided an adequate supply of oxygen for sockeye production. In comparison with eight other sockeye-producing lakes in Washington and Alaska, the concentrations of zooplankton in Ozette Lake appear adequate to support the rearing of sockeye salmon. In Big River and Umbrella Creek, tributaries to Ozette Lake, the streambed areas with gravels suitable for spawning were calculated to be about 39,000 and 31 ,000 square yards, respectively. If those areas were completely utilized they would accommodate about 13,000 and 10,000 spawning sockeye females, respectively. (Woodard-USGS)

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