"Estimating Water Budgets for WRIA..."

Today’s presentation will cover:

Why is it necessary to know how much water is present in WRIA 1?

How is the amount of water present estimated?

The Hydrologic Cycle

Actions by people affect the hydrologic cycle

Hydrologic Equation

To estimate the amount of water present in WRIA 1, the hydrologic equation needs to be solved.


This is referred to as estimating the water budget for WRIA 1.

Water Budget:
Near-Surface Component

Water Budget:
Ground-Water Component

Using a numerical model, water budgets may be estimated for subbasins

Why use a numerical model?

Summary of a numerical model

Slide 14

A model is calibrated by matching simulated and observed variables, including streamflow, snowpack thickness and extent, and others.

Steps required to simulate the water budget with a numerical model

Creating MRUs with the GIS Weasel

Yakima Model – MMS

Steps required to simulate the water budget with a numerical model

Precipitation

"Locations of Weather Stations in..."

Precipitation is distributed across the study area from known data points

Similar to precipitation, air temperature is distributed across the study area

Steps required to simulate the water budget with a numerical model

"Locations of Gaging Stations in..."

Streamflow

Streamflow

Surface Runoff

Ground-Water Discharge

Ground-Water/Surface-Water Interaction

"Generalized ground-water flow directions..."

Gaining Stream Reach

Losing Stream Reach

Snowpack Water Equivalent

Ground-Water Recharge

Evapotranspiration

Water use and returns are estimated across the study area

Slide 38

A calibrated numerical model may be used to simulate streamflows for different management options, including predevelopment conditions to estimate undepleted streamflows.

Streamflow volumes affect water quality (e.g. stream temperatures, dilution of chemical loading) and instream flow conditions that are important to fish (e.g. velocities of streamflow and sediment transport).

The water-quantity analysis will tie into a Decision Support System (DSS), which integrates such elements as water quantity, water quality, instream flows, and Best Management Practices (BMPs).

Example of a Decision Support System

MMS – Object User Interface

Yakima River, Condition of Algal Communities

DSS for the San Juan River Basin

DSS for the San Juan River Basin

Summary

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