Recharge and discharge estimation in data poor areas: UserGuide for the recharge and discharge estimation spreadsheets and MapConnect

[摘要] Determination of an accurate groundwater balance for a region requires estimation of recharge and discharge rates and, where possible, knowledge of their spatial distribution. Where the value of the resource warrants it, detailed recharge and discharge studies are commissioned. These studies provide comprehensive empirical information on spatial and temporal variability of recharge, and the relationship between recharge rates and soil, regolith, landform and vegetation parameters. Where the value of the resource does not warrant detailed research, much cruder approaches (such as recharge is a simple percentage of rainfall or discharge is assumed to be non existent) are used. The aim of the project described in this report was to develop a nationally consistent approach to recharge and discharge estimation for data poor areas which is a half way house between using simple approximations and carrying out very detailed field and modelling studies.This project involved two phases, the first of which compiled reviews of recharge and discharge studies that have been undertaken in Australia (Crosbie et al., 2010a; O’Grady et al., 2010). It also involved preliminary identification of the parameters (climate, soils, regolith, near-surface geology, landforms, vegetation etc.) that determine recharge and discharge rates along with a review of the appropriate scale mapping approaches available for these parameters (Pain et al., 2011). The second phase of the project utilised empirical relationships derived from data collected in Phase 1 of the project in a decision tree methodology that guides the user to the most appropriate estimate for recharge/discharge given the data availability. This report provides detailed instruction in the use of both recharge and discharge spreadsheets and the associated GIS datasets made available via Geoscience Australia’s MapConnect website. The number of methods that can be used will depend on the availability of climatic, hydrogeologic and land-use data but all methods are intended for areas where there have been no or few field-based studies undertaken. The intended users of the spreadsheet are hydrologists who have responsibilities in groundwater management.The Recharge Spreadsheet (Chapter 3) can provide up to three estimates of deep drainage and/or recharge using a range of empirically based relationships with climatic, hydrogeologic and land-use parameters. The Discharge Spreadsheet (Chapter 4) can provide up to three estimates of groundwater discharge based on three approaches: Groundwater Risk Model (based on the Water Balance Risk Model;WBRisk, (Howe et al., 2006)); Ecological Optimality, and a groundwater discharge versus groundwater salinity function.MapConnect and associated datasets (Chapter 2) provides the means to populate these spreadsheets in data poor areas.

[发布日期] 2011-08-16 [发布机构] CSIRO

[学科分类] 地球科学(综合)