Lake Whatcom Drinking Water: Is There Cause for Hope?

I’m sure it came as no surprise to those of you interested in the status of Lake Whatcom, our community’s primary drinking water source, to read on the front page of the April 9 Bellingham Herald that “Lake Whatcom Woes Persist” (Stark, 2014). The article is based on an interview with Dr. Robin Matthews, Director of the Institute for Watershed Studies at Western Washington University (Western), who oversees the annual monitoring of the lake as part of a contractual agreement between Western and the city of Bellingham (city). Dr. Matthews succinctly summed up the latest results by stating, “It’s not better, but it’s not getting bad as fast” (Stark, 2014).

Dr. Matthews has been monitoring annual water quality in Lake Whatcom for the city since the mid-1980s, though intermittent monitoring has been conducted since 1962. Monitoring consists of taking monthly water quality measurements and collecting samples for further laboratory analysis during the summer and at less frequent intervals in the winter, weather permitting.

Since Lake Whatcom is actually comprised of three subbasins, partially separated from each other by underwater sills, measurements and samples are collected from surface to bottom over the deepest areas of each basin (see map on page 11). The northernmost Silver Beach area basin, Basin 1 (sample Site 1) is approximately 100 feet deep. The Geneva area basin, Basin 2 (sample Site 2) is 40-60 feet deep. Basin 3 (sample Site 3, north part of basin, and Site 4, south part of basin) is 328 feet deep and contains 96 percent of the lake’s total volume.

In looking at the trends in the data results over the last several years, Dr. Matthews has noted a leveling off in the decline of some of the key water quality indicators, signifying to her that the lake may be stabilizing. These results are quite a change from data her research team collected in the early 1990s to the mid-2000s. During that time interval, water quality was not only declining at an alarming rate, it was accelerating in its decline with each passing year.

Dr. Matthews attributes the recent turnaround (within the last several years) and slowing in the rate of decline primarily to increased efforts by the city, Whatcom County, and the Lake Whatcom Water and Sewer District over the years to mitigate pollutant loadings to the lake. Since 1998, when the lake was listed as an impaired water body as defined under section 303(d) of the Clean Water Act by the Washington Department of Ecology (Ecology), millions of dollars have been spent and hundreds of hours of staff time have been dedicated to stop the decline.

Mitigation measures included upgrading existing stormwater treatment ponds, installing underground stormwater detention and treatment vaults, implementing building moratoriums, developing special regulations regarding when and how construction can occur, restricting the types of outboard motors that can be operated on the lake, restricting the use of phosphate-containing fertilizers, and purchasing undeveloped properties in the watershed.

Coupled with these measures were educational outreach programs to engage residents in the watershed and help to make them successful stewards of our community’s drinking water source. Targeted areas were the highly urbanized Silver Beach and Geneva subdivisions, since impervious surfaces and the actions by residents living in the watershed were the primary sources of pollutants entering the lake.

For example, some of you may remember the Lake Whatcom Watershed Pledge Program: “Drop by drop, stream by stream, all our waters can run clean.” It was initiated in the late 1990s by the city. Hundreds of thousands of dollars were spent on mailers, advertising and a website, and workshops encouraged residents to take the “pledge” and change their behaviors to be more lake-friendly.

Residents were made aware that changing the oil in one’s car, washing the car, fertilizing the lawn, or leaving pet waste on the ground could generate pollutants that could all end up in the lakes, streams, rivers, and oceans that support and sustain us. The program was a great first step and eventually transitioned into the Lake Whatcom Management Program’s stewardship efforts.

What the Data Show

The following is a synopsis of the most recent Lake Whatcom Monitoring Program Annual Report, Water Year 2012/13 (Matthews et al., 2014):

Surface water temperatures were slightly warmer than usual in spring and early summer.

Dissolved oxygen (DO) levels dropped to less than 1 mg/L from 14 meters (~46 feet) down to the bottom in Basin 1 by August (see Figure 1).

Median near-surface summer total phosphorus (TP) levels continue to decline in Basins 2 and the south end of Basin 3 from highs measured in 2010 and 2011, respectively (see Figure 2). Basin 1 and the northern part of Basin 3 had slight increases in TP, but only TP levels in Basin 1 were above the 5 ppb analytical detection limit (dotted line). Long-term trends over a 12-year span indicate levels may be stabilizing.

Median near-surface summer chlorophyll (Chl) concentrations continue to decline in Basin 1 and Basin 3 north, most likely in response to decreased TP levels there, whereas Basin 2 levels are unchanged from last year and Basin 3 south has increased slightly (see Figure 3). Long-term trends indicate:

• Basins 1, 2, and 3 north biological productivity levels seem to have stabilized and returned to 2004 levels.

• Basin 3 south continues to increase in biological productivity and is similar to levels measured in Basin 1.

Bluegreen bacteria (Cyanobacteria) populations were at higher levels in all three basins, but still below the maximums measured in 2005 (see Figure 4). The log-transformed plotted data emphasizes the stabilization of population numbers over the last 9 years.

Algal blooms during the summer months again clogged the city’s water treatment filters for a fifth year in a row causing poor water filtration rates at the water treatment facility. Only the early implementation of voluntary water restrictions enabled the city to provide sufficient quantities for both household and business uses.

Preliminary tests using Dissolved Air Floatation pretreatment method as a means to remove algae in the raw lake water before it enters the treatment facility have been encouraging. To build a full-scale facility will cost taxpayers millions of dollars.

Trihalomethanes (THMs), which are known carcinogens, continue to be at high levels in our tap water, especially in late summer and fall, but remain below the maximum contaminant level of 0.08 mg/L (see Figure 5). [Note: The number of sites used to calculate the quarterly averages increased from four to eight in 2012 (vertical dotted line)].

What Does it Mean?

Let’s start with oxygen, the single most important factor (besides water), essential for the survival of all aquatic organisms. Low oxygen levels in the bottom waters of Basin 1 have been below 2 mg/L in August for thirteen years out of 20 (1993 – 2013) (see Figure 1). According to the USEPA, dissolved oxygen levels below 5 mg/L stress aquatic life, and the lower the DO levels, the greater the stress. Levels that remain below 1-2 mg/L cannot sustain aerobic aquatic organisms.

Looking at the August data for Basin 1 at a depth of 14 meters (46 ft) from 1988 through 2013, levels have varied over the last 20 years but remained below 2 mg/L throughout. Some people have interpreted the variation to imply that things are improving, but “dead zone” means exactly that and 1 mg/L increase of oxygen above or below 1 mg/L makes no difference. I think of that catchy tune by Billy Preston “Nothin’ from nothin’, leaves nothin’….”

What about phosphorus? Looking at the data for total phosphorus from 1988 through 2013 (see Figure 2), levels in all three basins began to increase in 2000 but seem to level off over time, and actually decrease in the last three years in basins 1 and 2, and decrease in Basin 3 in the last 2 years. This is one of the key water quality indicators to which Dr. Matthews referred in the newspaper article.

Whether this trend will continue remains to be seen, since lakes respond to phosphorus inputs from the watershed and from internal recycling from the sediments. It is interesting to note that Basin 3, which is considered the most pristine in water quality, has phosphorus levels similar to Basin 2 with its urbanized sub-watershed.

Chlorophyll concentrations, the next set of data, are an indicator of algal biomass and therefore considered an important indicator of water quality. Algal biomass is directly related to the amount of nutrients, particularly phosphorus, available to algae to grow and reproduce. Since it takes time for biological organisms to respond to changes in their chemical environment, there is usually a lag period before a change is measured.

Chlorophyll concentrations in Basins 1, 2, and 3 north are continuing to show decreases that appear to show a leveling off since 2005/2006. Basin 3 south, however shows chlorophyll concentrations continuing to trend up, indicating that biological productivity is still increasing.

Cyanobacteria, which are encased in mucus-like sheaths and are responsible for water taste and odor problems, continue to remain in high numbers and show a slight increase in all three basins. At least their levels have remained fairly constant for the last ten years.

Other water quality indicators not depicted, such as total organic carbon (TOC) and dissolved inorganic nitrogen (DIN), show that biological productivity is leveling off in Basins 1 and 2, but not (yet) in Basin 3, especially in the south part of the basin.

Like Dr. Matthews, I concur the data seem to be indicating that our community’s efforts to increase protections from pollutant and nutrient loadings are making a difference, at least in the urbanized Basins 1 and 2. To put things in perspective, it has taken us approximately 20 years and millions of dollars to see slight improvements in those basins, and yet they each contain only about two percent of the total volume of the lake. Just think what it will take our community to effect positive changes in Basin 3, which contains 96 percent of the total volume of water.

We’ll get there, because we have to get there for the sake of our community’s health for generations to come.

• Matthews, R.A., M. Hilles, J. Vandersypen, R.J. Mitchell, and G.B. Matthews. 2014. Lake Whatcom Monitoring Project 2012/2013 Report. Prepared for the city of Bellingham, WA. March 6, 2014. 293 pages.

• Stark, J. 2014. “Lake Whatcom Woes Persist: Water quality not better, but decline slowing.” The Bellingham Herald, Wednesday April 9, 2014, pg A1 and A5.