The Water Quality of the Lake Whatcom Reservoir
Problems and Solutions

- (in plain language, so that non-technical people can grok.)
Download this as a word-processor DOC - LakeWhatcom-PlainText.doc .

Comments: send a message )

(Note: -- updated Dec-2016..)

Introduction: The Problems:

Surely most people believe that the Lake Whatcom Reservoir's water quality should be (must be) kept at a high quality? Lake Whatcom stores and supplies our drinking water, for all of the City of Bellingham and thousands of users adjacent to the city-limits, so it MUST be kept safe, Otherwise, people will get sick, and might even die. The Federal government thinks so, because the Reservoir is a major drinking water source, and they have issued a "Total Maximum Daily Load" order ("TMDL"), with a specific time when the pollution reduction must be satisfied. The TMDL order specifies a cap - the maximum amount of a specific pollutant - Phosphorus - that we are allowed to get into the whole lake each day. We cannot be sure what kind of a spanking the Feds are likely to give the City and County, but you can be sure we won't like it.  There are other pollutants, too, and everybody should work to reduce/eliminate them. Public health problems and costs are two of the negatives that we all want to eliminate.


Who is responsible for the low water quality? What affects the quality? And who has the ability to act so that we get and keep clean water for our drinking-water supply?

The responsibility is split, between the Whatcom County government, the City of Bellingham, the Lake Whatcom Water and Sewer District, and all the people who live on, and move on, the lands surrounding the Lake.

The watershed is the lands which form a "bowl", so that rainfall there will flow over the lands, and reach the lake. Within the watershed, about 9% of the land is in the City, and this has about 25% of the residential units; the County covers about 91% of the watershed land outside of the City limits, and has about 75% of the residential units, a large portion of which is in Sudden Valley.

Those answers are rather clear and straightforward, so why does this concern and risk remain unsolved for so many years?

The Problems:

First, we must be sure that everybody involved understands the problems, and has a fair basic understanding of the likely solutions.

The Sources of the Pollution:

Rainfall comes down clean when it lands on the surface of the Lake, and on the lands around it (the watershed). But when that water flows over and flows off of many of the parcels of land in the watershed, becoming polluted "runoff", it collects many chemicals that were lying on the surface. If left that way, it carries those pollutants into the lake. Prime among those pollutants are phosphorus (a fertilizer, the "P" of "N P K", and a naturally-occurring element) P-levels are actually much higher in a forest (compared to a developed site) but runoff from developed land moves more about 10x the amount of phosphorus into the lake. This is because a forested system manages and recycles its nutrients in a type of natural balance. Others are chemicals left by cars and trucks - oil, rust, and powder from brakes, animal and bird droppings, stuff dropped off of boats, and (AH! a BIG one!) construction which moves dirt around. Another source is natural deposition of leaves and pollen on hard surfaces (roofs, driveways, etc) which then enters storm systems during rain events. In recent years, the City and the County have stopped permitting construction (called "development"), but then they allowed it to continue.

Phosphorus feeds the growth of algae in the lake, and that algae becomes a stinky mess when there is a lot of it. It has clogged the water treatment plant, increasing costs, and requiring the use of more chlorine. Chlorine is one of the things which makes the water taste bad, but even more troubling, some chlorine compounds are chemicals remaining in the treated water, and which can cause cancer.

There is also a problem with other living things which are not natural here in Whatcom County, but can get brought into the area from elsewhere - "invasive species", which also disrupt the natural environment. The City now operates an inspection and cleanup program, located at the most-used boat launch in a City park -- but nowhere else.

How does water get into the reservoir? That which naturally comes in, is from direct precipitation, falling on the lake itself, and on the lands surrounding it which shed much of what falls there (aha! - a "watershed").

But what about water from other places? There is only one such flow - water brought from an upriver diversion of some of the flow of the Middle Fork of the Nooksack River. (A paper mill which operated on the waterfront since about the middle of the last century, but is now closed and demolished, needed a lot of water, and that was the supply for it.) That flow passes by gravity through a tunnel constructed for exactly that purpose, and it goes into the lake at the south end. The valve which controls flow from that diversion dam into the Lake is now remotely controlled, and these days remains either closed or with a very low flow most of the time. That water also carries some phosphorus, produced mostly by the decomposition of plants in the upland watershed of that fork of the River.

(Footnote: There is another big pipe that can take water from the lake - at a spot within the City - down to the industrial waterfront. It is now hardly ever used.)

"Lake" or "Reservoir"?

It is useful to also clarify the difference between the terms "lake" and "reservoir".

"Lake" probably needs little explanation - it is the body of water which fills a space that is wider and deeper than that of the streams or rivers which flow into it, because the flow out of that space is restricted or stopped by a natural or artificial dam. The lake is the body of water.

This lake became a Reservoir when two things were done long ago -

(1) at the outflow to Whatcom Creek, an artificial dam was built,

and (2) a pipe was installed from mid-lake to capture and send water to the City of Bellingham treatment plant for producing water which is "potable" (clean drinking water.) The LWWSD also operates a potable-water treatment plant, to serve its customers, the region called Sudden Valley.

The term "reservoir" includes the walls (of a tank) which hold the fluid - and in this type of reservoir, it includes the lands surrounding the body of water. The three responsible governments enacted a resolution in 1992 (link), identifying this area - the water and the lands around it - as The Lake Whatcom Reservoir, and defining 21 Goals.

Pollution Movement:

So, how does pollution get into the lake?

When it rains, some of that water falls onto both the constructed surfaces of building roofs and pavement, which are impervious, and onto natural ground, which is pervious in varying degrees. The runoff from the impervious surfaces usually flows immediately onto the ground surrounding them. Any polluting chemicals which were on those impervious surfaces can be captured by the flow, and carried downhill.

The overland flow can carry pollution, either dissolved or as suspended particles. Forestry and lawn areas both produce P and recapture it as a natural process. The amount of P which flows off such lands depends on many factors. A common source of P is leaves and lawns -- grass-clippings which are allowed to rot (decompose) on the ground. Particulate phosphorus is extremely immobile in the soil and is likely to stay wherever it is placed unless moved by erosion or crop export. Dissolved P is very easily moved around in saturated soil conditions.

The rainfall which lands on the ground and on the vegetation and forestry, (if nothing intervenes), naturally also flows downhill. The paths of most of the overland flow begins on lawns - then collects into small rivulets in low-spots, and next unites those into what may be called gullies or swales. The place where such a swale joins a creek, or leaves the property (going onto a neighboring parcel) is the best place for a rain-garden or other "stormwater management strategy", to treat, manage, detain, or infiltrate runoff. Once the polluted flow is in a creek, treatment becomes very difficult and expensive.

How can this pollution problem be fixed?

The actions needed to prevent that pollution from entering the lake can be considered in three ways – the first (easiest and cheapest) is -- control the pollution at the source.

First: do not let pollution ever lay forgotten on the ground where it could be captured by the runoff flow. The use of fertilizer that has "P" in it, is now prohibited in this watershed. Do not do things like car-washing, in a place where that runoff can flow to the Lake.

When lawns in the watershed are mowed, , the previous recommendation was to use the clippings-bag and move them into a composting-hole that has been dug, then covered over. The City has found that bagging clippings, over the long term, is not a solution to phosphorus discharge. While it may help in the short term, the lawn becomes robbed of other nutrients (N, K) and starts to die. Dying lawn holds less water and fewer nutrients. A dead lawn discharges all of its nutrients at or above the lawn surface, where it can enter a storm system. Dead lawn also results in bare soil that can erode. Or haul them away to a Clean-Green disposal site (...oops!) the City just shut it down in 2016! Now what? Take it to the front lawn of City Hall? (Uh! no.)

More expensive are - install some ways to filter the water, so that the undesirable chemicals are held back, and cleaner water flows away from the parcels and into the lake. The polluting chemicals that need to be filtered out may sometimes be biologically captured by the roots of the vegetation which is in the flow-path, or those chemicals may be caught and collected by a replaceable $creen, which mu$t then be hauled away.

Rain-Gardens - the best method;

The capture of phosphorus by the vegetation, is more simply done by a constructed feature called a "rain-garden". (Unless shallow groundwater or bedrock is present. In that case such a hole might be a good way to create a big supply of P just waiting for the 20 year storm to overflow the compost hole and wash all that dissolved P into the Lake.) A rain-garden is made in an excavated trench, placed in a spot so that the runoff over the land flows into it. You fill this little trench with selected porous soils, and re-plant it with certain kinds of native plants that are good consumers of phosphorus. Polluted water flows into the trench, and most of the phosphorus is captured by the roots, so cleaner water flows out of the rain-garden trench into the natural subsoil - perhaps eventually reaching the surface as a spring, or reaching the lake as an underwater spring. In the best installations, the water moves away, but most of the pollution never leaves the property. Phosphorus capture in a rain garden occurs via vegetative uptake, physical filtration, and soil chemistry. Other useful methods, according to the City, in developed lands, are: Reforestation (replace lawn with forest), dispersion (distribute all runoff into a large forested area that can absorb excess P), and treatment (filter water using natural or synthetic filters to remove/catch P). Other BMPs that are good (but more expensive) include infiltration trenches, permeable pavement, dispersion trenches, media filter drains, sand filters, and proprietary treatment devices.

Rain-gardens may be installed at numerous preferred locations on land parcels - usually near the lower side of the parcel so they capture more of the runoff. The size will vary, depending on how much flow it will need to capture, but for a common houselot, about the size of a couple of big dining-room tables.

For public roadway rights-of-way, rain-gardens would be installed at selected locations along the roadway to best capture flow, by matching the sizes of the rain-garden trenches to the area and water flow rate.

Mechanical filter-screens – not the preferred method;

One type of pollution-removal installation is a “treatment vault”. Such a vault is a constructed box (usually mostly underground, with concrete walls) which contains a porous screen or special cartridges, made of material that captures particles. It can capture P attached to particles, but cannot capture much dissolved P. The percentages are reported to have improved in recent years. Ordinarily, polluted water flows into the box, some of the undesirable chemicals are caught on the screen, and somewhat cleaner water flows out. But larger volume storm-flows cannot get through the small passages, so those large flows go past the box, untreated. Also, there are significant costs of construction, regular replacement of the screens or cartridges, and general maintenance.

So, What should the People and the Governments do?

To wrap up this explanation of these methods of control of pollution in runoff water to keep it from entering the lake (and thus into our drinking-water supply), a comparison of the costs of programs for installation and the management and maintenance, and the effectiveness of the alternative systems is a reasonable need – and some such phosphorus-removal cost/benefit analysis has been done, and is available from the City. We MUST meet the TMDL requirement of the Federal government (maximum allowable), by reducing the amount of phosphorus entering the water of the lake.

1) The first and best action is control at the source – all people and agencies must do the most possible, to keep P and all other pollutants from ever being in places (such as on the ground) where runoff flow can capture them.

2) For treatment vaults, the program is "easy" for the government - all it takes is more money for construction and maintenance--forever. But the usual percentage of P that they can capture is about 50%, although it can be higher for the really fancy and expensive filter systems, a poor return on investment of tax-payers money. The taxpayers must complain!

3) For rain-gardens, the installation and management of them on developed properties almost always requires involvement of the private landowners - even if there are some funds provided to offset part of their expenses. The good news is how much better the results are, in both measures -- the percentage of P that rain-gardens capture is usually much more than the 50% which has been typical of vaults. Similar results may be had from all infiltration, treatment, dispersion, and native landscaping projects. All may be cheaper for the taxpayer and more effective for the Lake. Of special interest are lakeshore lawns, since a rain-garden is just about the ONLY way to intercept runoff before it gets into the water.

4) We have to know how much P is going into the lake, and where that is happening. There is a program funded by the City of Bellingham, of sampling the water at multiple places all around the lake, to learn how much pollution is in that water. The biggest issue with in-lake sampling is that low levels of P might not be a good thing. If P is low, it could mean water quality is good, but it could also mean that all of the available P is bound up in algae and the water column itself is starved of nutrients. Then, when the algae die and release the P, there is a large surge that may not be captured in periodic measurements of surface waters. This water-quality sampling and reporting program must be continued.

The Best Treatment Program

Thus, it seems that the best program for the City and the County and the people, is to:

a) First, do source control -- don't put pollutants on the land or in the water, and the replacement of lawn with native vegetation and a thick mulch layer, then...

b) Next, do both types of treatment - with a strong first preference for installing rain-gardens on every parcel where they are practical, and a few treatment vaults (with their high maintenance costs and low percentage of capture of pollutants), only where these are the necessary second option.

    Report by WA State Ecology


   Dear Reader: We welcome your comments about this page, to make it more easily understood by the non-technical public.
       leave a message from the website

The Initiative Group -- Whatcom
Our bottom-line principles are:
Protect the water supply in perpetuity -- maintain ecological viability of the lake for natural species -- distribute the financial burden fairly among those benefitting -- take immediate action if prudent -- take definitive action -- avoid actions which cut off future options.
1992 Resolution
Back to the LW HomePage

leave a message from the website

page URL: href="LakeWhatcom.org/plain-language.html"
Bellingham, Washington 98226 --- The Fourth Corner of the USA
last edited Nov 23, 2015 -- mgb