• Violations of dissolved oxygen standards during the dry season led to a Total Maximum Daily Load (TMDL) study for WRIA 23 in 1994, and temperature standard violations led to another TMDL study in 1999.
• Field observations have indicated that removal of trees and other vegetation along much of the upper river has reduced shading, which contributes to high dry-season temperatures. The TMDL study recommends increasing vegetative shading along the Chehalis River and its tributaries.

The following is the key finding related to critical fish species for WRIA 23 (note that most of the habitat issues are discussed under the "Basin-Wide Findings" section):

• Of the eight Chehalis fish stocks identified in the Level 1 Assessment, five are considered to be healthy. The condition of the other three stocks is unknown.

WRIA-Wide Findings For Lower Chehalis Basin

The Level 1 Assessment presents some findings that apply to the whole Lower Chehalis Basin (WRIA 22) rather than to individual subbasins or study areas. The following are the key findings related to water rights and water use for WRIA 22:

• Irrigation and domestic uses are the primary purposes for the largest number of water rights. Power generation and domestic use are the primary purposes for rights with the highest total instantaneous withdrawal rates. Municipal uses and power generation are the primary purposes for rights with the highest total annual volume limit.
• Thirty of the 769 water rights in the lower basin account for 90 percent of the total allocated instantaneous withdrawal. The largest of these is a 1,400-cfs right for hydroelectric power generation on the Wynoochee River.
• Figure ES-3 compares lower basin water right allocations to Level 1 estimates of actual consumption for domestic use, irrigation and livestock watering. Allocated rights for each of these purposes greatly exceed the current estimated use.

The following is the key finding related to critical fish species for WRIA 22 (note that most habitat issues are discussed in the "Basin-Wide Findings" section):

• It was estimated in 1986 that gravel mining removed 10 times as much gravel each year as would be naturally replenished in these river systems. Such operations were reported in 1975 to have seriously reduced available spawning areas for chinook salmon on the Satsop, Humptulips and Wynoochee Rivers.

Findings for Study Area 1-Grays Harbor Subbasins

Study Area 1 consists of the nine subbasins that drain directly to Grays Harbor or the mouth of the Chehalis River. The major surface water systems in this study area are the Humptulips, Hoquiam and Wishkah Rivers and tributaries south of Grays Harbor. The following are the key findings related to hydrology for Study Area 1:

• Average annual rainfall ranges of 127 inches in the Humptulips drainage basin is the highest annual rainfall of all subbasins in the Chehalis Basin.
• High levels of rainfall throughout the study area lead to correspondingly high levels of runoff

The following are the key findings related to water rights and water use for Study Area 1:

• Study Area 1 has the lowest total number of rights of all the study areas.
• Rights in the Humptulips drainage basin account for almost half of the instantaneous allocation for the study area and almost two-thirds of the volume allocation.
• From May through October, the Humptulips River in-stream flow requirement alone, without the consumptive allocated water rights, exceeds the river's low flow.

The following are the key findings related to water quality for Study Area 1:

• The Grays Harbor TMDL identifies the Humptulips, Hoquiam, and Wishkah Rivers as major nonpoint sources of fecal coliform to the harbor, although the available water quality records reviewed for the Level 1 Assessment do not indicate a problem with fecal coliform in these rivers.
• Study Area 1 water bodies listed on the state's 303(d) list are the Humptulips River and inner Grays Harbor. A TMDL study has been prepared for the inner harbor and a TMDL for the Humptulips River is being prepared

The following are the key findings related to critical fish species for Study Area 1:

• The status of four of the 15 stocks identified on the rivers in Study Area 1 is unknown; the status of the other stocks is healthy.
• The Humptulips River has an extensive history of channel modification through gravel removal and the use of splash dams for forestry.
• Small streams tributary to the Wishkah River have good habitat complexity and in-stream structure.
• The Hoquiam River had a history of logging impacts through the 1930s. A diversion dam on the west fork supplies water to the City of Hoquiam.
• Historical channel modifications, mainly splash dams, were reported in the subbasins south of Grays Harbor

Findings for Study Area 2-Lower Chehalis Subbasins

Study Area 2 consists of eight subbasins draining to the Chehalis River downstream of Porter. The major surface water systems in this study area are the lower main stem of the Chehalis River, the Wynoochee and Satsop Rivers, and Cloquallum Creek. The following are the key findings related to hydrology for Study Area 2:

• No flow records are available for the lowermost reach of the river.
• The 123-inch average annual rainfall in the Wynoochee subbasin is the second highest of all subbasins in the Chehalis River Basin, with correspondingly high unit runoff of up to 12 cfs/mi2.
• Analysis of recorded flows at a gaging station near Aberdeen before and after the completion of the Wynoochee Fish Barrier Dam and the Wynoochee Dam shows that winter peak flows decreased after the dams were put into operation and summer low flows increased

The following are the key findings related to water rights and water use for Study Area 2:

• The permitted reservoir storage volume for the Wynoochee subbasin represents almost two-thirds of the total storage volume limit for the entire Chehalis Basin. The Wynoochee subbasin also has the largest allocation of instantaneous withdrawal rate, representing more than 40 percent of the total for the entire basin.
• The allocated annual water volume (total volume of permitted water use per year) in the Lower Chehalis Reach 2 subbasin is the largest of all subbasins in the Chehalis Basin, representing more than a quarter of the basin-wide total.
• Significant individual rights in the study area include an 80-cfs groundwater right for held by the Washington Public Power Supply System, a 570-cfs surface water right for multiple domestic use held by the Arrowhead Community Club1, a 400-cfs right for power generation in the Wynoochee subbasin, and rights of 110 cfs and 45 cfs held by the City of Aberdeen for municipal and commercial/industrial uses.
• In the Cloquallum subbasin, the flow demand (the sum of the in-stream flow requirement and the consumptive allocated water rights) exceeds the low flow from March through November. In the Lower Chehalis Reach 1 subbasin, the demand exceeds the low flow from March through October.
• In the Cloquallum subbasin, estimated domestic water use is about 12 percent of the allocated right. In the Lower Chehalis Reach 1 subbasin, estimated domestic use is about 13 percent of the allocated right and estimated municipal use is about 9 percent of the allocated right.

The following are the key findings related to water quality for Study Area 2:

• The only Study Area 2 water body listed on the state's 303(d) list is the Lower Chehalis River.
• Total suspended solids concentrations in the Satsop subbasins are second in the Chehalis Basin only to the concentrations in the Humptulips subbasin.
• The Grays Harbor TMDL identifies the Satsop River as a major source of fecal coliform to the harbor, although the available water quality records reviewed for the Level 1 Assessment do not indicate a problem with fecal coliform in this river.
• Temperature has frequently exceeded state standards at the Montesano monitoring station on the Chehalis River. This station also recorded the highest total phosphorus loading and yield of all stations on the Chehalis, as well as the highest yield of inorganic nitrogen, although neither have violated state standards.
• Two water bodies in Study Area 2 are listed on the state's 303(d) list.

The following are the key findings related to critical fish species for Study Area 2:

• The known status of five of the eight fish stocks identified on the Satsop and Wynoochee Rivers is healthy. The status of two of the stocks (Satsop summer chinook and Satsop winter steelhead) is depressed, and the status of Wynoochee spring chinook is disputed.
• The primary habitat problems noted in stream surveys are bank erosion, excessive sediments in the water and reduced tree canopy.

Findings for Study Area 3-Middle Chehalis Subbasins

Study Area 3 consists of three subbasins draining to the Chehalis River from Porter to near Grand Mound. The major surface water systems in this study area are a reach of the main stem of the Chehalis River, the Black River, and Cedar Creek. The following are the key findings related to geology and hydrology for Study Area 3:

• Black Lake previously drained to the Black River but, at least during the dry season, there is no longer a connection between the lake and the river, and the lake drains out of the Chehalis Basin into Percival Creek in Tumwater by way of a constructed drainage ditch.
• The 48-inch average annual rainfall in the Black River subbasin is among the lowest of all subbasins in the Chehalis River Basin. Estimated unit runoff in the study area is relatively low.
• The exchange of groundwater and surface water is significant in the area around the Black River, Middle Chehalis Reach 2 and Scatter Creek. Because of this hydraulic conductivity, the valley floors in this area have been designated critical aquifer recharge areas.

The following is the key finding related to water rights and water use for Study Area 3:

The following are the key findings related to water quality for Study Area 3:

• The Black River has experienced problems with temperature, dissolved oxygen, total phosphorus, ammonia-nitrogen and fecal coliform.
• Water quality monitoring records from the Porter station indicate problems with temperature and dissolved oxygen.
• Seven water bodies in Study Area 3 are listed on the state's 303(d) list.

The following are the key findings related to critical fish species for Study Area 3:

• Summer temperatures in the Black River and in Scatter Creek are high enough to prevent adult salmon from migrating upstream.
• The primary habitat problems noted in stream surveys are livestock access to streams, bank erosion, and the destruction or loss of bank vegetation.

Findings for Study Area 4-Upper Chehalis Subbasins

Study Area 4 consists of 10 subbasins draining to the Chehalis River upstream of the Lewis/Thurston County line. The major surface water systems in this study area are three reaches of the main stem of the Chehalis River, the South Fork Chehalis, Newaukum and Skookumchuck Rivers, and Elk and Salzer Creeks. The following are the key findings related to geology and hydrology for Study Area 4:

• Average annual rainfall is 42 inches in the Salzer Creek subbasin, the lowest of all subbasins in the Chehalis River Basin.
• Estimated unit runoff in the study area is relatively low, about 3 to 5 cfs/mi2.

The following are the key findings related to water rights and water use for Study Area 4:

• Study Area 4 has the highest total number of rights of all the study areas. More than half of the rights are for irrigation.
• The Skookumchuck subbasin has the second highest storage allocation of all subbasins in the Chehalis Basin, after the Wynoochee subbasin.
• Significant individual rights include a 140-cfs right held by Pacific Power and Light for power generation and an 80-cfs held by Pacific Power and Light for power generation and commercial use.
• In the Chehalis headwaters subbasin, the flow demand (the sum of the in-stream flow requirement and the consumptive allocated water rights) exceeds the low flow in every month except for November, December, February and March. In the Newaukum subbasin, the demand exceeds the low flow in every month except February.
• In the Chehalis headwaters subbasin, estimated domestic water use is about 4 percent of the allocated right and estimated municipal use is 16 percent of the allocated right. In the Newaukum River subbasins, estimated domestic use is as much as 81 percent of the allocated right.

The following are the key findings related to water quality for Study Area 4:

• A 10-mile portion of the main stem of the Chehalis River passing through Centralia and Chehalis, known as the Centralia Reach, has a special water-quality designation. A natural sill in this segment causes water to pool upstream, leading to slow-flowing waters and characteristics more like a lake than a river.
• Thirteen water bodies in Study Area 4 are listed on the state's 303(d) list.

The following are the key findings related to critical fish species for Study Area 4:

• The status of the only identified fish stock specific to Study Area 4 (the Skookumchuck/ Newaukum winter steelhead) is depressed.
• Some peak temperatures in parts of the study area have exceeded the lethal limit for many salmonid species.
• The primary habitat problems noted in stream surveys are bank erosion, loss of canopy and bank vegetation, and livestock access to streams.

Level 1 Recommendations

Based on its review of available data, the Level 1 Assessment provides recommendations for further investigations and analysis to be performed as part of a Level 2 Assessment. Key topics recommended for further evaluation in the Level 1 report are as follow

The interaction of groundwater with surface water Undepleted stream flows (not affected by human activities) and the influence of dams on flow The established requirements for in-stream flows The effect of land use on hydrology Options for augmenting stream flows The accuracy of the Washington State Department of Ecology's Water Rights Accounting and Tracking System

Actual water use relative to allocated water rights Water quality by subbasin Pollutant yields in priority subbasins The priority of potential water quality improvement actions Fish habitat conditions in the basins south of Grays Harbor and in the Wishkah and Hoquiam River basins Restoration opportunities for side channels, wetlands and sloughs.

In addition to recommending new analyses, the Level 1 Assessment recommends that long-term water quality monitoring stations be established in one or two places likely to represent a baseline condition that can be used for comparison.

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1 A Department of Ecology investigation has subsequently revealed that the units for this water right were entered incorrectly in the agency water rights database. The correct value is 570 gallons per minute (or 1.3 cfs) rather than 570 cfs.