Water Watch: Water supply update — Low levels not expected to improve much
With all of the news stories about the drought over the past year, it should be no surprise that our water supply is hurting. 2021 was a record year in terms of how little water the Weber Basin Water Conservancy District stored in its reservoirs on the Weber and Ogden rivers. This was in part due to the below average snowpack that accumulated in the Northern Utah mountains. The major factor that led to the dismal 2021 spring runoff, however, was record low soil moistures throughout the region. The record dry soils going into the snowpack season meant that a large percentage of the snow that had accumulated in the mountains went straight into the ground before ever reaching our streams and reservoirs. This record low spring runoff, coupled with the hot and dry spring and summer seasons, left our reservoirs and carryover water supply in bad shape.
This year, snowpack in the Weber and Ogden drainages is again below average, sitting at about 75% of where we’d be on a normal year, and just 52% of the average peak experienced (this peak typically occurs during the first week of April). This actually puts us right in line with where we were this time last year. Fortunately, soil moistures have been predominantly above average throughout the region since about mid-October of last year. This above average soil moisture should correlate to better runoff efficiency and more water making it to streams and rivers to supplement the little water that was left in our reservoirs at the end of last year. However, even with the above average soil moisture and associated runoff efficiency, runoff forecasts distributed by the Colorado Basin River Forecast Center are still only predicting reservoirs on the Ogden and Weber rivers to see about 40%-70% of typical runoff volumes.
As of right now, reservoirs on the Ogden and Weber rivers are at about 51% of capacity overall, with approximately 280,000 acre-feet of storage. That leaves a void of approximately 270,000 acre-feet required to fill reservoirs. With the current runoff projections, it’s safe to say that void will not be filled this year. In order to avoid dropping the reservoirs to record lows again this fall, and to ensure a drinking water supply for next year, Weber Basin Water is implementing restrictions on irrigation and drinking water contracts. These restrictions will initially consist of 60% reductions to residential outdoor uses, 40% reduction to agricultural uses and 10% reduction to culinary indoor uses. With these restrictions, the district is hoping to preserve about 120,000 acre-feet of water that would otherwise be used for primarily outdoor water use, thereby firming up drinking water supplies in case drought continues into next year.
Weber Basin Water Conservancy District is Northern Utah’s regional water supplier for treated municipal water, wholesale irrigation water, retail secondary irrigation water, untreated industrial water and groundwater replacement water.
Riley Olsen is the water supply and power manager for the Weber Basin Water Conservancy District. He is a registered civil engineer in Utah and has a master’s degree in civil engineering.