Lake Whatcom Decline Slowing?

April Markiewicz is the associate director and toxicologist in the Institute of Environmental Toxicology at Huxley College of the Environment, Western Washington University, member of the city’s Lake Whatcom Watershed Advisory Board and president of the People for Lake Whatcom Coalition.

“Cautiously optimistic” was the phrase used by Dr. Robin Matthews, director of the Institute for Watershed Studies at Huxley College of the Environment, Western Washington University, to describe the latest Lake Whatcom monitoring data (Matthews, personal communication). She was referring to recent trends in the lake’s water quality data that she has been collecting for the city of Bellingham since the mid-1980s.

The data indicate the rates at which conditions have been degrading in the lake may be slowing down, at least in the short term. Her caution is that the slowing rates could be due to the unusually cold temperatures we had in May and October of 2007 and the even colder temperatures that occurred throughout all of 2008 (Matthews et al., 2009).

As many of you know, Lake Whatcom (see map) has served as the primary drinking water source for Bellingham and parts of Whatcom County dating back to the early 1900s. Currently the lake provides drinking water to more than 96,000 residents, including all of Bellingham and approximately half of the county. It also continues to serve as a recreational destination for residents and tourists alike, as well as provides a home to more than 6,500 households in its watershed.

Our community is very fortunate to have such an invaluable resource. We are also fortunate to have such good data about our primary drinking water source that enables us to see trends in the lake’s water quality over time. We can thank our forward-thinking city officials who have supported and funded ongoing studies of Lake Whatcom since the 1960s.

We can also thank Dr. Matthews and her team of researchers who have conducted that monitoring since the mid-1980s. As a result of those monitoring efforts, we have a very accurate record of how the lake’s water quality has changed since then, especially as our use of and activities in the surrounding watershed have increased over the last 20 years.

In a recent public presentation (Matthews, 2009) Dr. Matthews summarized where the lake is now:

• The entire lake has changed to a higher level of productivity than it was even a few years ago.

• The quality of Lake Whatcom water is still high, but it is no longer at the level it used to be.

• Phosphorus levels have increased throughout the lake.

• Algal densities and chlorophyll concentrations have increased throughout the lake.

• Odor and taste issues are becoming more prevalent.

• Treating the water has become more expensive because of all these increases.

• Levels of suspected cancer-causing byproducts in our treated water have increased.

The most recent data published in the 2007/08 Lake Whatcom Monitoring Final Report (Matthews et al., 2009) show that overall conditions in the lake have remained relatively the same; however, some changes were noted. The data show the following:

• 2008 surface water temperatures during May through July were the coldest measured since 1988.

• Thermal stratification of the lake in late spring was delayed due to the cold weather, but extended longer into fall compared to 2007.

• Dissolved oxygen (DO) levels measured at depth in May and August were still relatively high compared to previous years’ data due to the late stratification (Figure 1).

• Green algae and especially blue-green algae, which are less tolerant of colder water, were less abundant (Figure 2).

• Nutrient levels in the surface waters of the lake during summer were as follows:

❏ Nitrate and nitrite were higher in all three basins (Figure 3).

❏ Total phosphorus (TP) continued to increase in Basin 3, especially at Site 4, compared to the last four years of data (Figure 4).

❏ TP levels in Basin 1 declined slightly and dropped below analytical detection limits in Basin 2 compared to previous years’ data.

• Nutrient levels in the deeper waters of the lake during summer were as follows:

❏ TP levels in Basin 2 levels were the highest ever recorded (Figure 5), in Basin 3 (Site 4) the levels were at least double the levels measured since 2004, and in Basin 1 the levels were higher than any other year except for 1988 and 2005.

❏ Ammonia levels in Basins 1 and 2 in November were the highest ever recorded, with Basin 2 data off the scale (Figure 6). Levels in Basin 3 continued to be elevated, similar to previous years’ data.

The decrease in TP found in Basins 1 and 2, in conjunction with the decrease in algae has lead Dr. Matthews to suggest that phosphorus concentrations may (her italics) be stabilizing in those basins, which in turn could be stabilizing their algal populations (Matthews, 2009; Matthews et al., 2009).

The increase in nitrates/nitrites she attributes to less algal abundance, since more algae would consume more nutrients. The importance of this suggestion is that those basins may have adapted to and compensated for the current level of phosphorus loading, causing less algal growth to occur. That does not mean the lake and its water quality are getting better, only that phosphorus and algal levels have possibly leveled off, at least in the short term.

Basins 1 and 2 are still very nutrient enriched and have high levels of biological productivity in them. The evidence is in the severity of dissolved oxygen deficits once the lake becomes stratified and the increasing amounts of TP and ammonia being released from the sediments over the summer months. Moreover, Basin 3 (Sites 3 and 4) phosphorus and ammonia levels are continuing to increase, showing the same signs of nutrient enrichment seen over the years in Basins 1 and 2.

Dr. Matthews also readily admits in an interview with The Bellingham Herald (Stark, 2009) that the water quality results for Basins 1 and 2 could be due to the unusually cold weather last year which made some of the results appear better than they would have been otherwise.

The lake must be restored to meet the requirements of the federal Clean Water Act (Pickett and Hood, 2008) and state regulations. Currently the lake is listed under section 303(d) of the Clean Water Act as an impaired waterbody for dissolved oxygen and phosphorus. By restoring the lake to meet federal and state standards we are also ensuring that it continues to be “... a clean source of drinking water, supports fish, birds, plants and animals, and provides aesthetic and recreational value to the community.” (Pickett and Hood, 2008).

The Washington Department of Ecology (Ecology) has conducted a Total Maximum Daily Load (TMDL) analysis for phosphorus and bacteria (Pickett and Hood, 2008). Using 2002 Lake Whatcom water quality data to calibrate their model, Ecology determined that phosphorus loadings need to be reduced by 18 to 40 percent (pre-1988 levels) for the lake to be able to process it and still meet federal and state standards.

Since there is a direct relationship between impervious surfaces (roads, roofs, driveways, decks and lawns) in developed areas and phosphorus levels in stormwater runoff, that reduction equates to reducing the amount of developed acres (as of 2003) in the watershed by 85.5 percent. Stated another way, there are 3,600 acres in the watershed that are developed, but the model says the level should be 524 to 563 acres (Pickett and Hood, 2008).

We need to focus on removing those sources of phosphorus that we can control (Hood pers. comm.). Since those sources are directly linked to stormwater runoff from developments and impervious surfaces, the solution is to reduce those sources.

One mechanism is to increase infiltration of stormwater runoff to enable the natural properties of soil and resident microorganisms to bind and use the phosphorus before it enters the lake. For example between 1986 and 1998 development doubled in the watershed, but regulations to retain canopy cover and implement stormwater controls did mitigate the effects of that development. The lake still got worse during that period, but not as bad as if those controls and actions weren’t taken (Hood pers. comm.).

Capturing and treating the stormwater runoff from these sources is another mechanism. Matthews et al. (2009) reports continued improvements in particle and fecal coliform removal due to redesigning the city’s Park Place Pond. Moreover, phosphorus removal has also improved due to increased maintenance of the city’s stormwater treatment vaults. For example the Alabama Hill stormwater treatment vault had an average total phosphorus reduction of –2 percent between 2004 and 2006. In 2007 the reduction was at 18 percent and in 2008 at 25 percent.

Understandably, there is some skepticism regarding the use of stormwater treatment vaults due to their expense and relatively low level of effectiveness in removing phosphorus. Indeed, earlier data showed higher levels of phosphorus leaving the treatment vaults than what entered in the stormwater. Subsequent studies, however, found that the data results were a function of when the vaults were sampled.

According to Matthews (pers. comm.), during the dry summer months dust and soil particles would enter the vaults and accumulate on the treatment canisters. When the first major rain event occurred in the fall, the water entering the vault scoured the accumulated particles off from the canisters and carried them out of the vaults. Samples collected at the inflow and outflow during that first fall storm event therefore showed higher levels of phosphorus and particles leaving the canisters than what entered.

Although these treatment systems are improving, they are not at the 80 to 90 percent levels needed in reducing phosphorus in stormwater runoff. Every technique, however, that helps reduce phosphorus loadings to the lake is crucial to restoring it as our community’s irreplaceable clean drinking water source.

The city and county can only do so much. It will also require people living in the watershed to stop stormwater runoff on their properties from entering the lake. Some methods people can use include installing natural rain garden systems, using porous pavement materials for driveways and paths, converting to ecologically based wastewater treatment and water reuse systems, and harvesting rainwater for irrigation or other reuse systems.

Sue Taylor has taken that level of responsibility a step further and started an educational opportunity for watershed residents called “Sustainable Landscaping for Watershed Living.” It is a hands-on, free educational pilot project working with homeowners to encourage gardening practices that reduce stormwater run-off by adding vegetated buffers, reducing impervious surfaces, and improving soil to increase its ability to absorb and slowly release water. It is time for all property owners in the watershed to take responsibility for their actions and the effects of those actions on our community’s primary source of drinking water.

Ecology has informed the city and county of what needs to be done to restore the lake to meet federal and state laws. The city and county are now charged with providing a plan to Ecology outlining how they will achieve those requirements and the time frame. Ecology admits it will be a daunting task for our community. It will take a lot of money and a lot of time to restore the lake.

They estimate just getting to 74 percent fewer developed acres/impervious surfaces (at 2003 levels) will take almost two generations (about 60 years). Even addressing runoff from all the roads in the watershed is estimated to take more than 20 years. Ecology further cautions that seeing changes to phosphorus and dissolved oxygen levels in the lake will also take decades. Those changes will be subtle, making it even more difficult to keep political leaders and the public engaged, and supportive of the resources being expended.

All of us need to be engaged now. The studies have been done and the targets we have to reach identified. We are ultimately responsible for protecting and restoring our drinking water source. Our elected city and county officials need to be asked what limits they are going to put on development in the watershed. If they continue to allow some development to occur then they need to be clear with us how much more they are going to allow.

Every new house, driveway or road that is built in the watershed is only going to contribute that much more phosphorus loading into the lake. Those contributions, no matter how small, will mean that much longer for us to clean up the lake, with all of us paying an even greater price for generations to come. §

• Matthews, R.A. 2009. Lake Whatcom Water Quality Monitoring Program Update. Presented to the Lake Whatcom Technical Review Task Force on March 17, 2009, Bellingham, WA. Available online at http://www.ac.wwu.edu/~iws under Lake Studies - Lake Whatcom Online PDF Reports, Presentations.

• Matthews, R.A., M. Hilles, J. Vandersypen, R.J. Mitchell, and G.B. Matthews. 2009. Lake Whatcom Monitoring Project 2007/2008 Final Report. March 2009. Institute for Watershed Studies, Western Washington University, Bellingham, WA, 317 p. Available online at http://www.ac.wwu.edu/~iws under Lake Studies - Lake Whatcom Online PDF Reports, Annual Reports.

• Pickett, P. and S. Hood. 2008. Lake Whatcom Watershed Total Phosphorus and Bacteria Total Maximum Daily Loads Volume 1: Water Quality Study Findings. Publication No 08-03-024, November 2008. Washington Department of Ecology, Olympia, WA. 145 p. Available online at www.ecy.wa.gov/biblio/0803024.html.

• Stark, J. 2009. “Lake Whatcom quality appears stable.” The Bellingham Herald, April 5, 2009, page A1 and a correction on April 7, 2009, page A1.