A healthier pond, it won't be crystal clear
Media: Fianna Dickson, 625.6297. Parks & Recreation: 311
Tuesday, June 23, 2020 at 2:31 p.m.
SPOKANE – Visitors to Manito Park will see a healthier Mirror Pond as the result of a recent rehabilitation project. The pond was dredged, deepened, and a treatment wetland is being installed in the next few weeks – all to reduce large algae blooms that were removing oxygen from the water.
A healthy pond is not completely free of algae, but has moderate enough amounts to benefit the ecosystem of the pond without removing too much oxygen from the water. Mirror Pond will not be crystal clear or bright blue, but it will be clearer and is healthy again.
The community can help keep the pond healthy by not feeding the geese, and avoiding the introduction of non-native fish, such as goldfish, into the pond.
The project was completed with financial support of the Friends of Manito and City Parks funds, as part of the Mirror Pond master plan. The Friends of Manito contributed $75,000, and the Park Fund contributed $367,000 for a total project cost of $442,000. A winding pathway around the pond was previously completed as part of the master plan.
Pond background
The pond turned green over a number of years due to planktonic algae. Buildup of broken down organic material on the bottom of the pond had loaded the water with both nitrogen and phosphorous, which are great foods for algae.
The pond was also shallow, and there was not enough water above the pond floor to filter out light, which aids algae blooms. Algae is not harmful to pond ecosystems in small amounts; however large blooms remove oxygen from the water, harming wildlife.
The restoration project combats this algae buildup. The pond was dredged to remove sediment, and then deepened to increase the volume and keep water cooler. Wetland plantings are being installed to reduce the future buildup of phosphorus and nitrogen. Water and indigenous wildlife have been reintroduced to the pond.
The project began in late fall 2019, and was planned to be completed the spring. The project was delayed 1-2 months because of suppliers closing due to COVID-19.
About City of Spokane Parks and Recreation
City of Spokane Parks and Recreation stewards nearly 120 properties across 4,000 acres of park land, including manicured parks, conservation lands, aquatic centers, golf course, sports complexes, and an arboretum. We also offer hundreds of recreation opportunities for all ages and abilities to improve the health and quality of life for our community. Enjoy all your city has to offer by visiting spokaneparks.org. Follow us @SpokaneParks on Facebook, Instagram, and Twitter.
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