Water Quality Decline Has Slowed

April Markiewicz is the associate director and toxicologist in the Institute of Environmental Toxicology at Huxley College of the Environment at Western Washington University, as well as president of the People for Lake Whatcom Coalition.

According to the latest Lake Whatcom Monitoring Program Annual Report for 2010-11 (Matthews et. al., 2012), our community’s primary drinking water source continues to decline in water quality. The rate of decline has slowed as indicated by some water quality parameters; however, other parameters continue to increase above federal and state clean water standards set to protect human and aquatic health. As a scientist looking at the most recent data, I would conclude, as does Matthews et. al. (2012), that overall trends continue to be variable, but do not appear to have stabilized or reversed, indicating that the lake is still not showing signs of recovering.

As a Bellinghamster quenching my thirst with a cool glass of tap water I would go further and conclude that our community’s drinking water quality has crossed the line of no return. For me the defining moment was getting up in the middle of the night last fall and taking a drink of water from the glass I keep by my bed. The taste was such that at first I thought one of my cats had drank out of it just after eating its favorite seafood buffet canned cat food.

Subsequent experimentation and careful observation, however, revealed that the taste of my tap water was untainted by any cat, but rather the product of our city’s water treatment facility. At that moment, I realized how far our water had degraded from when I first moved here 31 years ago. I also realized that since we continue to allow impacts to the lake from our activities on it and in the surrounding watershed, the lake would not, at least in my lifetime, ever return to the high quality drinking water source we used to have.

I now have an end-of-the-tap water filtration system in place and though my water tastes flat, it is preferable to drinking water that tastes like pollywog bath water. I know that our treated water from Lake Whatcom is in compliance with all state and federal regulations for tested chemicals, bacteria, and particles and meets or exceeds all safe drinking water standards. As a human though, my taste buds obviously have a different set of standards and according to them our drinking water fails the taste test.

Unfortunately, there are many other people in the community who have resorted to purchasing some type of filtration system to improve the taste of their drinking water. The tragedy of the situation is that had each household made the same investment in protecting Lake Whatcom and its surrounding watershed 10-20 years ago it makes now in purchasing filtration systems and replacement filters we would not be facing the problems in water quality we are today.

What Has Changed, If Anything?

Compared to the previous year, the rate of decline in the lake’s water quality has slowed according to Matthews et. al. (2012). Dr. Matthews, Director of the Institute for Watershed Studies at Western Washington University, attributes the slowing to unusually cool water temperatures throughout spring and summer of last year. As you may recall from other annual reports by Dr. Matthews and her research team, there is a strong correlation between water temperatures and biological productivity in the lake. Warmer temperatures not only speed up thermal stratification of the lake, preventing deeper waters from mixing with surface waters, it also increases biological productivity in the lake. Algal blooms are not only more severe, but they start earlier in the spring and last later in the fall. Those blooms not only clog the water filtration system at the city’s water treatment facility, they also support greater bacterial growth.

Bacteria feed on dead algae and consume dissolved oxygen from the surrounding waters in the process. This speeds up the rate at which unoxygenated dead zones form in the deeper waters of the lake and prolong the time that these areas persist into late fall. Many substances including phosphorus, metals (e.g., mercury and lead), and sulfides in the sediments dissolve readily into the overlying anoxic water. So the longer the water is not oxygenated, the more substances are released from the sediments. Once the lake cools and mixes in late fall these substances (and the anoxic water) are re-circulated throughout the lake, causing adverse effects to both human and aquatic health.

Conversely, below normal cooler temperatures result in the opposite effects, i.e., thermal stratification occurs later; algal and bacterial productivity decrease; oxygen deficits in deeper waters are less severe, and concentrations of nutrients and other sediment-bound pollutants dissolved in the overlying waters are lower. Colder temperatures can also alter species dominance. For example, cold tolerant blue-green algae are out-competed for resources by the more tolerant green algae and so they tend to dominate in colder years (see Figures 4 and 5).

As you look at the data in the figures, keep in mind that 2003 through 2005 water temperatures were unusually warm, resulting in the data showing accelerated increases in algal numbers, total phosphorus, and chlorophyll (an indicator of algal biomass), with concurrent severe oxygen depletions once the lake stratified. Moreover, data from the four sampling sites show that all three basins of the lake were adversely affected (see Figures 1- 5). Conversely, in 2007, 2008, 2009 and 2010 temperatures were unusually cold and the data reflect a slowing of the degradation and in some instances a reversal in trends. Long-term water quality monitoring reveals, however, that though there can be wide variability in data from year to year, the overall trends are progressively downward even with the tempering effects of cooler temperatures.

Long-term Monitoring

As some of you may know, the Institute for Watershed Studies (IWS) in Huxley College of the Environment at Western Washington University celebrated its 50-year anniversary earlier this year. Most of those years were spent conducting studies of the water quality conditions in Lake Whatcom, the drinking water source for all of Bellingham and half of Whatcom County. The studies were mostly funded by the city of Bellingham as part of its responsibility as the authorized water purveyor to comply with state and federal regulations.

As a result of those studies the city has a comprehensive, almost 50-year record of water quality conditions in the lake and how those conditions have changed over time. The data provide irrefutable evidence that conditions are declining and that the lake is becoming more impaired as a drinking water source. In 1998, the Washington Department of Ecology (Ecology) listed the lake as an impaired water body as defined under section 303(d) of the Clean Water Act. In other words the lake water no longer met clean water standards established to protect human and aquatic life because it contained too much phosphorus, dieldrin (a chlorinated persistent insecticide banned in the 1970s), polychlorinated biphenyls (PCBs), and mercury, as well as too little oxygen (CH2MHill, 2008).

The primary cause has been linked to residential development and our recreational activities in the watershed that have contributed to nutrients, particles, and other chemical contaminants entering the lake via stormwater runoff. Unfortunately, development has been allowed to continue in the watershed to the present, though more restrictions have been implemented by the city of Bellingham, Whatcom County, and the Lake Whatcom Water and Sewer District. Additional stormwater treatment facilities have been installed in the heavily developed residential areas located at the north end of the lake to reduce particle and nutrient loadings to the lake.

Regardless of these efforts, the lake’s water quality continues to degrade, exceeding safe and clean water quality standards to a greater extent each year. Though cooler temperatures help to temper and slow the rate of decline, all three basins of the lake (see map on page 1) are affected and will continue to decline even if all inputs of phosphorus and other external inputs of contaminants stopped today.

What the Data Show

Despite the cool spring and summer with concurrent late onset of thermal stratification in the lake, dissolved oxygen levels dropped, but not as quickly as nor to levels measured in 2010 (see Figure 1).

Median near surface summer total phosphorus levels decreased slightly in the two northern, shallow basins, but continued to increase throughout Basin 3 where most of the water is located (see Figure 2).

Median near-surface summer chlorophyll concentrations decreased slightly in all three basins compared to record-setting high levels measured in 2009-10 monitoring year (see Figure 3).

Algal blooms during the summer months again clogged the city’s water treatment filters for a third year in a row causing poor water filtration rates at the water treatment facility. Only the early implementation of voluntary water restrictions prevented mandatory restrictions from being imposed later in the summer (Figures 4 and 5).

Ammonium and hydrogen sulfide formed under anoxic conditions by bacterial degradation were lower in concentration than usual. Matthews et. al. (2012) suggested this may have been due to cooler temperature conditions that shortened the length of time the lake was thermally stratified.

Trihalomethanes (THMs), which are known carcinogens, continue to increase in our tap water (see Figure 6). THMs are formed when organic particles (dead bacteria/algal cells) not removed during the filtration process interact with chlorine used to disinfect the water before being distributed to households. The more particles there are, the more THMs are produced. Washington state’s Maximum Contaminant Level for total THMs (WAC 246-290-310) is 0.08 mg/L.

Tributaries flowing into Basin 3 at the southern half of the lake have relatively low concentrations of particles, metals, and nutrients. This area is primarily composed of rural and commercial forestry with scattered residential development.

Residential tributaries flowing into Basins 1 and 2 at the north end of the lake have higher concentrations of particles, metals, nutrients, and fecal coliform bacteria.

The highest water inputs into the lake are from surface and subsurface runoff (75.1 percent), followed by direct precipitation (18 percent) and water diverted from the Middle Fork of the Nooksack River (6.9 percent). Inputs from runoff are approximately the same compared to last year; however, precipitation decreased by ~6 percent, whereas supplemental water from the Nooksack River increased by ~4 percent.

Highest outputs from the lake are via Whatcom Creek (81.2 percent), city of Bellingham (9 percent), evaporation (7 percent), Whatcom Falls Hatchery (2.1 percent), Lake Whatcom Water and Sewer District (0.6 percent) and Puget Sound Energy Co-Generation (0.1 percent). Outputs via Whatcom Creek increased by ~6 percent, but residential water usage decreased by almost 3 percent most likely through voluntary water conservation efforts.

In Summary

Similar to previous year’s findings, our drinking water source continues to decline in water quality. Efforts by the city of Bellingham and Whatcom County to reduce untreated stormwater runoff inputs to the lake from the residential areas have made a difference in keeping the rate of decline lower. Preserving undeveloped forested lands in the watershed provides even greater protection to the lake from future residential development and contaminant loadings to the lake.

The city of Bellingham deserves commendation for its efforts over the last eleven years to acquire undeveloped properties in the watershed at fair market value. It also recently increased the water fee rate to provide additional funding and support for its land acquisition program, as well as stormwater runoff control measures in the watershed.

The Whatcom County council also deserves special commendation for its recent decision to approve the reconveyance of approximately 8,000 acres of forested board lands in the watershed that are currently managed by the Washington Department of Natural Resources back to county control. Utilizing those lands as low impact parklands will ensure that surface and groundwater inputs from those lands will not contribute any future contaminant loadings to our drinking water source.

The take-home message is that degradation of water quality in Lake Whatcom may be slowing down in the short term, but overall water quality is not improving. We need to remain diligent in our efforts to eventually stabilize and eventually reverse the trend. The bottom line: I think we all want our drinking water to pass the taste test, for us and our future generations.

References