Surfacewater Quantity and Quality

All of the streams in the northern Puget Sound watershed have two annual peak periods of streamflow. The highest one occurs in the fall (October through November) when the most precipitation falls, and the next peak occurs in the spring. In terms of rainfall, the driest months are June, July, and August. The low-flow period occurs at the end of summer, mid-August through September. A comparison of the hydrographs for Nooksack River (glacier and precipitation-fed) and a lowland tributary, Fishtrap Creek (precipitation-fed), shows how the seasonal runoff patterns and volume levels can differ.1

San Juan Island Water Resources2

The chief supplies of fresh water occurring in the San Juan Island map-area are found in the large and elevated lakes on Orcas, Blakely, and San Juan Islands.

On Orcas Island, Mountain Lake, with an elevation of 915 feet, and Cascade Lake, with an elevation of 350 feet, are capable of supplying a moderately large quantity of water at all seasons of the year. Buck Lake, Killebrews Lake, and the Twin Lakes also contain a considerable volume of water. The large bogs occurring on Mount Constitution Range and other locales in the map-area are capable of retaining a remarkably large volume of water. The water derived from the relatively heavy precipitation which falls on Mount Constitution Range is naturally conserved so efficiently that numerous streams issue from all sides of the range at all seasons of the year. Orcas Island is abundantly supplied with water.

On Blakely Island, Thatcher Lake, with an elevation of 188 feet, and Blakely Lake, with an elevation of 374 feet, are capable of supplying a considerable volume of water.

San Juan Island has three lakes of moderate size, Sportsmans Lake, Trout Lake, and Egg Lake. The water resources of San Juan Island are somewhat limited except in the northern portion where the rocks of the Orcas group are encountered. The underground water supply is found especially in the fractured cherts of the Orcas group, and artesian wells have resulted on Shaw Island in some instances when the overlying Leech River sediments were penetrated.

Lopez Lake, with an elevation of 91 feet, is the only body of surface water occurring on Lopez Island. Water can be readily obtained, however, by penetrating certain impervious strata in the glacial sediments that cover the greater part of the island.

Several small lakes occur on Cypress Island, but their combined volume of water is very small.

The smaller islands of the San Juan group are occasionally so lacking in fresh water that a species of prickly cactus may be found growing on them. It is very remarkable, however, that some of the small, bare, rocky islands, which are isolated from the others by exceedingly deep channels, have an abundance of freshwater at a depth of 40 or 50 feet below the surface.

Nooksack Water Quality Monitoring3

Nooksack Watershed Whatcom County

Portage Bay is located at the terminal end of the Lummi Peninsula and approximately three miles down the shore from the mouth of the Nooksack River. The intertidal area of Portage Bay is a major commercial shellfish harvesting area owned and operated by the Lummi Nation. Until recently, all of Portage Bay held an Approved commercial shellfish growing area designation.

The principal source of fecal coliform data for Portage Bay comes from the Washington State Department of Health (WDOH) Shellfish section. WDOH conducts monthly sampling of eleven stations in the Portage Bay area for purposes of shellfish growing area classification. Fecal coliform samples are collected jointly with Northwest Indian College and analyzed at the WDOH laboratory in Seattle using the Most Probable Number (MPN) technique. Other parameters sampled include salinity and temperature. WDOH uses the most recent thirty samples collected from each station to determine the classification status of a particular shellfish growing area.

The Washington State Department of Ecology (WDOE) Environmental Investigations unit generated the principal source of fecal coliform data for the Nooksack River watershed. The WDOE conducted a Total Maximum Daily Load (TMDL) assessment of the Nooksack watershed and collected water quality samples at least monthly from March 1997 until February of 1998. Fecal coliform samples were analyzed by Membrane Filter and MPN methods. Also sampled were E. coli and various physical parameters.

Fecal coliform sample locations along the Nooksack River also have been identified and sampled by Northwest Indian College (NWIC) staff monthly from April 1997 to date under various grants. Fecal coliform samples were analyzed by the Membrane Filter method at the DOE certified laboratory of the Northwest Indian College.

Results from WDOH sampling led to a downgrade in August of 1997 of a portion of Portage Bay. The downgrade derived from the failure of WDOH stations 50 and 51 to meet the standard for Approved commercial shellfish growing water. The standard violated was a 95% confidence level in excess of 43 fecal coliform per 100 milliliters of water. In response to this downgrade, a Portage Bay Closure Response Team was formed in order to develop a strategy to reopen the closed beds by December 1999. Both the Portage Bay Closure Response Team and the WDOH identified dairy waste practices in the Nooksack River watershed as the most probable source of the excessive fecal coliform concentrations. In September of 1998, Lummi Natural Resources staff identified an additional WDOH station (Station 52) as failing, based on a data review of WDOH field data.

The rationale for listing dairy waste as the most probable source of excessive fecal coliform concentrations in Portage Bay is the recognition that the 50,000 dairy cows on the 200 dairy farms in the Nooksack watershed form the largest source of fecal coliform of the possible sources investigated. The linkage between the Nooksack River fecal coliform counts and Portage Bay is generally established by the incidence of low salinity recorded by WDOH while sampling for fecal coliform. In general, the incidence of high fecal coliform concentrations in Portage Bay coincides with lowered salinity values that are indicative of freshwater influence. The primary source of freshwater to Portage Bay is the Nooksack River.

While this linkage from cow to clam is demonstrable, it is not yet predictable. A primary goal of the water quality monitoring program has been to develop such a predictable model. If a predictable model could be developed, areas of Portage Bay which are now in a Restricted status could be upgraded to Conditionally Approved. A Conditionally Approved status would allow for direct marketing of shellfish under certain predictable conditions. Furthermore, identification of fecal coliform source as well as timing could focus efforts on controlling identified sources, and eventually result in a return to Approved classification status for all of Portage Bay.

The lack of ability to predict high fecal coliform concentrations in Portage Bay results from the plethora of environmental variables that influence the transport of fecal coliform from cow to clam. Results from inspection of the WDOH database reveal that fecal coliform concentrations in excess of the 95% confidence limit standard of 43 cfu/100ml normally occur when Nooksack River flow is over 7,000 cfs, or when river discharge is over 3,000 cfs and precipitation was greater than 0.7 in during the previous two days. River discharge below 2,500 cfs rarely yields violations of the standard. Violations of the standard also appear to be seasonally related. Most of the violations for Stations 50 and 51 occur in the months of October and April, while most of the violations for Station 52 that do not occur in October and April occur in the summer months. Results from these types of data analysis reveal the complex nature of the dynamics of fecal coliform transport and point to the difficulty in predicting high fecal coliform concentrations in Portage Bay, especially when there appears to be seasonal differentiation in transport dynamics. Qualifiers such as "most" and "rarely" indicate qualitative relationships rather than the quantitative relationships necessary for predictability.

Given that interpretations of WDOH data are currently more qualitative than quantitative, progress has been made in source identification and general transport mechanism. The predominant mechanism for transport of excessive fecal coliform concentrations to Portage Bay seems to occur when rainstorms wash excessive fecal coliform from dairy lands and river channels into the Nooksack River. As a result of storm runoff, river flow increases. The high river flow, combined with the southerly winds associated with rainstorms, can serve to direct this concentrated discharge along the shoreline and into both inner Bellingham Bay and Portage Bay. This mechanism seems to be predominant during fall and spring months. Coincidentally, these are also the times of maximum dairy waste application, as dairy farmers empty their lagoons in preparation for winter, and then again in spring empty lagoons filled from winter storage. Another mechanism can occur to a lesser extent during dry summer months and during periods of low river flow. In this scenario a relatively thin layer of Nooksack River freshwater can flow directly from the Nooksack River mouth along Brant Island and out Bellingham Bay past Portage Island. As summer months are typically times of lower fecal coliform concentrations in the Nooksack River, the magnitude of water quality violations at WDOH stations in Portage Bay tends to be lower as well.

So how have things been going over the last four years? Annual results of Centennial Clean Water and Environmental Protection Agency grants have been compiled based upon the water year originally sampled by EPA in 1997 (April-March). The most critical station for Portage Bay shellfish is M1 (Nooksack River mouth at Marietta). Results for M1 show a consistent decrease in fecal coliform concentrations at the mouth of the Nooksack River.

Current fecal coliform sampling in the Portage Bay Shellfish Protection District includes the continuing efforts by WDOH and additional sampling in Portage Bay, the Nooksack River, and selected tributaries through a Washington State Department of Ecology Centennial Clean Water (CCW) Act grant.

Under the current Centennial Clean Water Act grant, some 64 stations are sampled in the Portage Bay and Drayton Harbor Shellfish Protection Districts. Sampling frequency is generally at least twice per month.

References Cited

1. United States Geological Survey (USGS) Water Resources of Washington. Daily Streamflow for Washington. <http://waterdata.usgs.gov/wa/nwis/discharge>

2. McLellean, Roy. 1927. The Geology of the San Juan Islands. University of Washington Press. Seattle, WA.

3. Northwest Indian College Research Department. Water Quality Information Page. <http://nwic-research.org/waterQualityInfoPage.html>