Drought preparedness in Mt. Rainier National Park

Science Center Objects

The Issue: Water supply for park operations and backcountry users is determined by the spatial extent of perennial streams in Mount Rainier National Park (MORA). In addition, the presence or absence of streamflow (flow permanence) is related to water temperature, which influences the occurrence and distribution of aquatic species including cold-water fishes and insects. Information about the reliability and permanence of water supply in MORA is needed by park managers to plan for sustainable water supply in the future as park visitation is expected to increase and the park aquatic biota become increasingly impacted by droughts, which are also expected to increase in the future.

How USGS will help: The work proposed herein will address 1) the need for high-resolution information on drought sensitivity of park water resources, and 2) the corresponding need to apply this information to allow MORA to identify specific, on-the-ground actions to reduce drought vulnerability.

Unnamed stream in Mt. Rainier National Park with a streamflow status of “dry”

Unnamed stream in Mt. Rainier National Park with a streamflow status of “dry”

(Credit: Emily Rhoades, NPS. Public domain.)

Problem: Surface water flowing in streams is a critical water supply to Mt. Rainier National Park facilities. Currently, the Park does not have accurate estimates of the extent of streams that have surface flow year round (perennial), including the late summer low flow period when many streams go dry. In addition, there is a need to understand if and how perennial and non-perennail streams are sensitive to changes in climate and physical conditions that could affect timing of surface flow. 

Objectives: This project will update the current PROSPER model (PRObability of Streamflow PERmanence) to provide more accurate estimates of streams that do and do not have year-round flow. Estimates will be at 30-m resolution for streams throughout Mt. Rainier that is consistent with the National Hydrography Dataset Medium Resolution river network. Estimates are spatially continuous and are based on qualitative flow/no flow field observations and relations to landscape and climatic hydrologic drivers, including channel and valley morphology, groundwater availability, and climatic influences (e.g., snow and glacier runoff, summer precipitation). 

Relevance and Benefits: Results from the model will provide a database on streamflow permanence in Mt. Rainier Park and will inform park management on areas that are sensitive to stresses of low surface water availability necessary for park water resource needs or critically important aquatic biota such as protected bull trout and salmonid species. 

Approach: The project will update the PROSPER model using new flow/no flow field observations collected by NPS personnel using the FLOwPER mobile application (Jaeger and others, 2020). Local predictor variables that may influence streamflow permanence in a glacial, high alpine mountain setting will also be included. New variables include more detailed geology, higher resolution precipitation, glacier and snow cover extent, and local channel and valley morphology including valley aspect, channel slope and valley confinement.