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Wapato Park Improvements

About Wapato Lake
Wapato Lake was formed approximately 15,000 years ago during the retreat of the Fraser Ice Sheet. The lake was likely formed as a basin in glacial drift, created by a block of ice which melted after the retreat of the main ice sheet. The area was once a heavily forested rolling plain. Vashon Till underlies the area.

Keeping Wapato Lake's water clean has been a challenge throughout the park's history. Early efforts included adding chlorine to cut down on algae growth. Then in 1936, as part of a Works Progress Administration project to improve the park, 180,000 cubic yards of mud was dredged from the lake hoping to clean it. By 1942, the lake was closed to swimmers due to unhealthful water conditions. Since that time a variety of other methods have been tried to keep the lake water clean such as harvesting aquatic plants, adding millions of gallons of fresh water, and even draining the lake in 1981 and removing tons of polluted sediment.
Regularly draining or flushing the lake with fresh drinking water, however, is neither financially nor environmentally sustainable. In 2012, Metro Parks and the City of Tacoma agreed on a scientifically based approach to improve the quality of the water in Wapato Lake.  Wapato Lake is actually a giant catch basin, filled by stormwater runoff from the surrounding watershed. The water contains high concentrations of phosphorus and other nutrients which promote the growth of toxic algae, harmful to people and pets.
Scientists and engineers agree that the only way to consistently reduce the concentration of phosphorus is to effectively clean the stormwater coming into the lake and move the water through the lake at a faster rate. The most efficient way to channel more stormwater through the lake is to dismantle a bypass system set up at Wapato Lake in the 1970s (based on the mistaken idea that it would help). However, this is only part of the solution. It is important to remove phosphorus and other nutrients, which feed the algae, to improve the quality of water introduced to the lake. Part of the strategy is the cautious use of alum to bind the phosphorus into the sediment, thus making it unavailable for algae growth, without harming the lake's wildlife.

Over the past several years, frequent blooms of blue-green algae in Wapato Lake have produced potentially harmful toxins. Tacoma-Pierce County Health Department, which tracks water quality, has issued intermittent health advisories to warn people and pets to avoid areas of the lake that may have algae.

In the May of 2017 Metro Parks hired a contractor to disburse alum, or aluminum sulfate, in the water. The alum binds with phosphorus in water and sediment, forming a cap of aluminum phosphate on the lakebed. One application of the treatment is expected to be effective for about five years.

2008-2012 - Wapato Park Improvements including paved pathway, off-leash area for dogs, utility improvements (new fire protection-water line service to the Bathhouse and the sanitary sewer connection to the north picnic shelter), irrigation system enhancements, parking lot repairs. Design was by SiteWorkshop. Work was funded by the Parks Improvement Bond Measure, approved by the citizens of Tacoma in November of 2005 and an RCO grant. City of Tacoma contributed for irrigation ($6,747).

2011 - City of Tacoma Easement for Alaska Street Improvements as part of the City's $6 million project to improve Alaska Street from 56th to 72nd Street. Work in the easement included grading that gently sloped the hillside between the street and park, an ADA accessible pathway from Alaska Street into the park, and landscaping with native vegetation.
2008-2009 - Lakeshore plantings completed to reduce erosion, reduce use by water fowl and reduce water mixing from wind. Work was funded by the Parks Improvement Bond Measure, approved by the citizens of Tacoma in November of 2005 and grants from Pierce Conservation District, Dept. of Ecology and CTED.
2008 - Treatment of the lake with alum by Tetra Tech to reduce the number of blue-green algae outbreaks for the next 5 years.
2008 - Miranda Property Acquisition & Demolition - This was the last private home on the lake.  Work was funded by the Parks Improvement Bond Measure, approved by the citizens of Tacoma in November of 2005 and an RCO Grant.
2008 - Bathhouse Restoration - This project repaired the Bathhouse following significant fire damage from arson and provided upgrades to the restrooms, roof, exterior walls, doors, windows, concession space, heating, plumbing, ventilation, security and other building systems. Work was funded by the Parks Improvement Bond Measure, approved by the citizens of Tacoma in November of 2005 and fire insurance.
2007 - Vuu Property Acquisition - This was one of the two remaining residential properties within Wapato Park. Work was funded by the Parks Improvement Bond Measure, approved by the citizens of Tacoma in November of 2005.
2006-2007 - Management of Water Quality Report completed by Tetra Tech following the collection of water quality data from Wapato Lake over a one year period. Water quality samples quantified phosphorous, temperature, dissolved oxygen, pH, Secchi disk, Chlorophyll a and phytoplankton. Lake levels and outflow data were also collected and external loading was tested at three locations. A phosphorous modeling program was developed for the lake to assist in predicting the effectiveness of alternative future management recommendations. Wapato Lake is laden with high levels of phosphorus, resulting in seasonal toxic algae outbreaks. Recommended Phase I alum treatment, shoreline plantings and public education projects by Metro Parks will improve water quality in the near term while longer-term approaches addressing source issues within the surrounding watershed can be studied and addressed.
2005 - Master Plan - A new master plan for Wapato Park based on the ideas of a Wapato Park Master Plan Citizens Steering Committee and attendees at three public meetings, a final design was developed for the future of Wapato Park and approved by the Board of Park Commissioners at their November 10, 2005 Board meeting.
Wapato Park Master Plan Graphic
Contents (PDF 507 KB)
Project Overview, Vision Statement, Design Principles (PDF 1778 KB)
Master Plan for Wapato Park, Implementation (PDF 1308 KB)
Community Process, Historical Overview, Existing Conditions (PDF 1894 KB)
Concept Plan, Improvement Projects (PDF 1582 KB)
Appendices - Cost Estimate, Annotated History, Meeting Minutes (PDF 676 KB)
Project Administrator: Kristi Evans, (253) 305-1054

Installed domestic water fixtures. Lighting retrofit to be completed.