Each year, the Portland Water Bureau develops a Seasonal Water Supply Augmentation and Contingency Plan also known as the Summer Supply Plan. This plan evaluates the availability of water from the Bull Run and groundwater sources, projected weather forecasts, and water demands to guide management of the drinking water system. Between careful management and the region’s strong conservation efforts, the Portland Water Bureau is prepared to meet the range of potential supply and demand conditions that could occur in the Portland water system this season.
The Bull Run water system is designed to capture and store rainfall from the rainy season to provide adequate water supply during the dry summer months. The approximately 9.9 billion gallons stored in the two Bull Run reservoirs along with summer stream flows is sufficient to meet water demand during most years. During drier years, the Columbia South Shore Well Field groundwater source can be used to augment the Bull Run supply. This secondary source of reliable, high quality water can be used to make up any supply deficits. Because you can never be too safe, the City has also identified additional contingency sources and strategies to address even the most severe conditions.
Drawdown occurs each year when Portland Water Bureau customers use more water from our reservoirs than streams carry into them. This happens every year until the fall rains return and refill the reservoirs. Drawdown typically occurs around July 4. This year, drawdown began on June 30.
The Portland Water Bureau is prepared to meet drinking water needs of our customers. The Bull Run is a low-elevation watershed that gets its water primarily from rain, not snow. The watershed gets approximately 135 inches of rain each year, about 3-4 times more rain than we get here in town.
The Columbia South Shore Well Field is Portland’s secondary water supply. The well field has 26 wells in three aquifers that are capable of producing nearly 100 million gallons per day. Each year the Portland Water Bureau performs a groundwater maintenance operation during drawdown to ensure the wellfield is operational in the event it is needed for emergency supply. This operation is planned to begin on July 25 and may last until mid-August.
With an average daily summer water demand of 126 million gallons, it can take careful planning to meet the needs of our customers.
The Water Bureau’s best partner in ensuring that we have more than enough water for years to come is you! From 2004 to 2014, Portland’s population grew by 18 percent—but the city’s total water use decreased by 13 percent. This water savings is partly a result of how Portlanders have embraced water-saving technology and changed behaviors to make the most of each drop.
The Water Bureau has an efficiency program, where you can learn more about using water wisely all year round with information about native plants in your garden and low-flow devices for your showers, faucet and toilets. You can learn more at www.portlandoregon.gov/water/efficiency.
The Portland Water Bureau carefully monitors water levels, weather forecasts, and water use patterns to ensure adequate, clean water for all of our customers. As it does every year, the Portland Water Bureau is carefully watching our water supply through the summer. For updates and more information, visit www.portlandoregon.gov/water/summersupply.
Photo by Roman Johnston