Documentation of a deep percolation model for estimating ground-water recharge

Abstract

A deep percolation model, which operates on a daily basis, has been developed to estimate long-term average groundwater recharge from precipitation. It has been designed primarily to simulate recharge in large areas with variable weather, soils, and land uses, but it can also be used at any scale. This report documents the physical and mathematical concepts of the deep percolation model, describes its subroutines and data requirements, and describes the input data sequence and formats. The physical processes simulated are soil-moisture accumulation, evaporation from bare soil, plant transpiration, surface-water runoff, snow accumulation and melt, and accumulation and evaporation of intercepted precipitation. The minimum data sets for the operation of the model are daily values of precipitation and maximum and minimum air temperature, soil thickness and available water capacity, soil texture, and land-use. Long-term average annual precipitation, actual daily stream-discharge, monthly estimates of base flow, Soil Conservation Service surface-runoff curve numbers, land-surface altitude-slope-aspect, and temperature lapse rates are optional. The program is written in the FORTRAN 77 language with no enhancements and should run on most computer systems without modifications. Documentation has been prepared so that program modifications may be made for inclusions of additional physical processes or deletion of ones not considered important.

Hydrogeologic setting and preliminary estimates of hydrologic components for Bull Run Lake and the Bull Run Lake drainage basin, Multnomah and Clackamas counties, Oregon

“…The computer model was developed by Bauer andVaccaro (1987, 1990) to estimate long-term average groundwater recharge from precipitation in areas with variable weather, soils, and land uses. The model is based on practical and relatively easily implemented physical relations and estimates the components of the hydrologic budget for a basin, including changes in soil moisture, soil evaporation, plant transpiration, surface-water runoff, snow cover, and interception and evaporation of precipitation from the vegetation.…”

Simulation of groundwater and surface-water flow in the upper Deschutes Basin, Oregon

“…In addition, the 2004 model simulates the groundwater component of streamflow and not other components that are important to the overall response. Moreover, because groundwater recharge was calculated using a separate surface-process model, the Deep Percolation Model (DPM) of Bauer and Vaccaro (1987), using the 2004 groundwater model for future climate simulations requires operation and maintenance of a separate model.…”

“…38) averaging about 56 percent of precipitation over the simulation period; a figure consistent with other studies. Basin-wide evapotranspiration calculated by Gannett and others (2001), using the DPM (Bauer and Vaccaro, 1987) averaged 53 percent of precipitation from 1962 to 1997. Manga (1997) estimated evapotranspiration to range from 27 to 60 percent of mean annual precipitation in four catchments in the Cascade Range where mean annual precipitation ranged from 42 to 69 in/yr.…”

Estimates of ground-water recharge to the Columbia Plateau regional aquifer system, Washington, Oregon, and Idaho, for predevelopment and current land-use conditions

“…The deep-percolation model was developed early in the study, and is documented by Bauer and Vaccaro (1987). During model development, the data base needed for the recharge estimation was developed, and a data-base management system was established.…”

“…Cell values were estimated by one of two distance-weighted interpolation schemes using data from nearby weather stations (described by Bauer and Vaccaro, 1987). Adjustments to the daily precipitation for a cell were made by multiplying it by the ratio of average annual weather-station precipitation to the average annual cell precipitation.…”