Watching the water supply:

Southwest Washington bearing brunt of dry conditions

Although we don't expect much rain this time of year, one area of the state stands out for being drier than usual: Southwest Washington and most of the Olympic Peninsula.

The July 19, 2018, U.S. Drought Monitor map classifies

southwest Washington as having moderate drought-like

conditions. Much of the rest of the state is considered

abnormally dry.

The U.S. Drought Monitor map, one of the tools we use to assess state water supply conditions, classifies much of the region as experiencing moderate drought-like conditions. The map is updated weekly and available on our statewide water supply conditions webpage.

Streamflow data also point to low flows in the region.

We’re seeing many rivers and streams in southwest Washington run at record low levels. The Chehalis River near Grand Mound is running at 113 cubic feet per second—a flow level in the 1st percentile, meaning flows are so low they are exceeded 99 percent of the time for this time of year historically. The Willapa River near Willapa is at 20 cubic feet per second, which is in the 1.5 percentile, meaning the flow is exceeded 98.5 percent of the time for this time of year historically. Irrigators, fish and aquatic habitat are most affected by these low flows.

Citing low flows in the Cowlitz River, the city of Kelso has asked its residents to take  

The Chehalis River winds its way west of Chehalis (July 19, 2018). We're
seeing record low flows on parts of the river. 

voluntarily water conservation measures until water levels in the municipality’s water source improve. To the north, the city of Forks and two small Jefferson County water systems are also asking their customers to follow voluntary conservation measures.

NOAA’s climate prediction center is predicting warm, dry conditions for the rest of summer. We are closely monitoring water supply conditions and working with other state agencies to track impacts. If you’d like more detail, read our water supply webpage.

Are we in a drought emergency?

Under Washington State law, emergency drought conditions are identified when water supply in an area has or is predicted to have 75 percent of normal water supplies AND undue hardships expected as a result. 

Drought emergencies are declared using a formal process based on statute. At this time, we have not declared a drought emergency anywhere in the state.

A rain-fed water system

The hydrogeology of southwest Washington is unique. Water supplies rely heavily on rain and less on snowpack from the Cascade and Olympic mountains. This means the region’s water supplies are more sensitive to above-average temperatures and below-average precipitation like we’ve been experiencing.

The effects of the unseasonably warm and dry weather in May led us to issue water use curtailment notices. We asked 88 junior water right holders—mostly irrigators—in the Chehalis River basin to stop using river water until flows increase.  This is the fourth consecutive year we have issued curtailment orders or notices for junior surface water irrigation uses in the basin. It was also among the earliest dates we have curtailed this group of water users.

Office of Chehalis Basin

In 2016, the Legislature created the Office of Chehalis Basin within Ecology. While a main focus of the new office is to pursue long-term flood-damage reduction and restore aquatic habitat in the state’s second-largest river drainage system, the Office of Chehalis Basin is also tracking the impacts of the dry conditions.

By Kristin Johnson-Waggoner, communications manager