Assessment of groundwater availability from recession flows and instream flow requirements of rivers in South Africa

Simple item page
cg.contributor.crpWater, Land and Ecosystems
cg.coverage.countrySouth Africa
cg.coverage.iso3166-alpha2ZA
cg.coverage.regionSouthern Africa
cg.identifier.wlethemeDecision Analysis and Informationen
cg.numberKV 339/15en
cg.placeGezina, Pretoria, South Africaen
dc.contributor.authorEbrahim, Girma Yimeren
dc.contributor.authorVillholth, Karen G.en
dc.date.accessioned2016-12-21T06:31:23Zen
dc.date.available2016-12-21T06:31:23Zen
dc.identifier.urihttps://hdl.handle.net/10568/78429
dc.titleAssessment of groundwater availability from recession flows and instream flow requirements of rivers in South Africaen
dcterms.abstractGroundwater is an important resource for multiple uses in South Africa. However, setting limits to its sustainable abstraction while assuring basic human needs is a must. Due to prevalent data scarcity related to groundwater replenishment, which is the traditional basis for estimating groundwater availability, the present report presents a novel method for determining allocatable groundwater in quaternary catchment through information on streamflows. Using established methodologies for assessing baseflows, recession flows, and instream ecological flow requirements, the methodology develops a combined stepwise methodology to determine annual groundwater storage volumes in the catchments using linear reservoir theory, essentially linking low flows proportionally to upstream groundwater storages. The approach was trialled for twenty-one perennial and relatively undisturbed quaternary catchments with long-term and good streamflow records. Using the Desktop Reserve Model to estimate instream ecological flow requirements of the streams and equating these with ecological groundwater reserve, excess baseflows were converted into groundwater storages on an annual basis. Results show that groundwater development potential exists in nineteen of the catchments, with upper limits to allocatable groundwater volumes ranging from 0.01 to 1.58 MCM/yr over the catchments. With a secured availability of these volumes 75% of the years, variability between years is assumed to be manageable. A significant (R2 = 0.86) correlation between baseflow index and the drainage time scale for the catchments underscored the physical basis of the methodology and also enables the reduction of the procedure by one step, omitting recession flow analysis. The method serves as an important complementary tool for the assessment of the groundwater part of the Reserve and the groundwater directed measures.en
dcterms.accessRightsLimited Access
dcterms.bibliographicCitationEbrahim, Girma Yimer; Villholth, Karen Grothe. 2015. Assessment of groundwater availability from recession flows and instream flow requirements of rivers in South Africa. Gezina, Pretoria, South Africa: Water Research Commission. 60p. (Water Research Commission Report KV 339/15)en
dcterms.isPartOfWater Research Commission Reporten
dcterms.issued2015en
dcterms.languageen
dcterms.publisherWater Research Commissionen
dcterms.subjectgroundwater rechargeen
dcterms.subjectgroundwateren
dcterms.subjectwater storageen
dcterms.subjectwater availabilityen
dcterms.subjectwater allocationen
dcterms.subjectwater requirementsen
dcterms.subjectstream flowen
dcterms.subjectflow rateen
dcterms.subjectriversen
dcterms.subjectcatchment areasen
dcterms.subjectdrainageen
dcterms.subjectenvironmental flowsen
dcterms.subjectrainen
dcterms.subjectmultiple useen
dcterms.subjectecological factorsen
dcterms.subjectaquifersen
dcterms.typeReport

Files

License bundle

Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.87 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections

IWMI Reports
Decision Analysis and Information
Managing Resource Variability and Competing Use