By Karen Galt and Todd Burley
Plants need water, and those that are subject to heavy use like turf grasses require even more to remain healthy. Every year, Seattle Parks and Recreation (SPR) uses nearly 176 million gallons of water for irrigation in our 6,414-acre park system! We work daily to manage our water sustainably, using what we need to maintain healthy parks that can be enjoyed by the public while also conserving water where we can.
This task of making every drop count has grown in complexity over the last decade with increasing summer drought conditions due to climate change. Seattle and the surrounding region have had our driest and hottest years during the last decade, including the two hottest days on record just this summer. To maintain our plants, we need to use a variety of methods to conserve water.
Before we even start watering, SPR employs several water conservation measures. This includes adding arborist wood chips and leaves around trees, in garden beds, and in other areas. Plants get water through their roots in the soil, and many strategies are directed at retaining moisture in the soil. Wood chip mulch retains moisture during the summer drought through absorption and evaporation reduction. Another method is to plant native and drought-tolerant plants in most areas, and ensure these plants get a good start by increasing the length of time they are watered during their establishment period. Once they are firmly rooted, they require less water in the long run. We also have increased our mowing heights to three inches, which increases shade at the soil, creates healthier grass, and reduces evaporation. Finally, we let some grass go into natural dormancy during the summer, which saves on irrigation while allowing the plants to rebound when the rains naturally return in the fall.
When it comes to irrigation and watering, we save water by targeting our resources on high priority areas. These include active use areas such as athletic fields, play areas, specialty gardens, near wading pools and spray parks, and in areas that host large events. In addition, we prioritize new plantings and food gardens. This supports our objectives with irrigation, which are to support our “living assets” while also supporting the community.
In all there are over 350 irrigation systems within our larger system, some of which are 50 years old. Over the years SPR has invested in “smart” irrigation that ties into actual local weather conditions and is customized by on-the-ground knowledge from our gardeners and grounds crews; about 75% of SPR’s irrigation water use is managed by these systems. These allow staff to adjust irrigation to where it is needed most using “zones” and through intelligent irrigation timing, such as watering at night and automatically adjusting sprinkler run times based on current weather.
SPR staff are constantly identifying issues, adjusting, and repairing damage in our irrigation network in order to make every drop count. We monitor real time data and conduct annual irrigation training to ensure staff are prepared to maintain this system. Yet we cannot be everywhere all the time. If you see a broken irrigation line or sprinkler head, or another issue related to irrigation, please let us know! Send a note to “PKS_Work_Order_Desk@seattle.gov” and we will investigate. Thank you for your help!
July is Smart Irrigation Month, and there are ways you can make every drop count, too! Seattle Public Utilities hosts some great tips and resources on their My Lawn and Garden page. Or visit the Saving Water Partnership Lawn & Garden webpage to learn even more. Seattle is familiar with summer droughts, but we know they will increase in intensity with the impacts from climate change. Plan now to ensure you are also managing our water resources sustainably.