Modeling for Inter-Basin Groundwater Transfer Identification between Middle Abay River Basin and Upper Awash River Basin
No Thumbnail Available
Date
2017-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Groundwater flow models are important for the identification of inter-basin groundwater
transfer between adjacent basins. Numerical groundwater model, TAGSAC has been used to
study the inter-basin groundwater transfer (IBGWT) between middle Abay River basin and
upper Awash River basin. Three steady state groundwater flow models (for middle Abay River
basin, upper Awash River basin and for the two combined basins) were first created and
calibrated for the inventoried wells. The first two models were created by considering the
surface water divide between the two basins as a no flow boundary. The third model avoids the
surface water divide which justifies IBGWT. The calibration target for this study was the
hydraulic head; hydraulic conductivity and surface recharge were used as calibration
parameters. The goodness of fit indicators (GoFIs) that was obtained for the third model was
better than the other two models. This indicates the evidence of IBGWT between the two
basins; i.e. groundwater flows from middle Abay River basin to Upper Awash River basin and
from Upper Awash River basin to middle Abay River basin. In addition, the groundwater head
distribution for third model showed that the groundwater divide and surface water divide were
not coincident. And groundwater is easily accessed within a shallower depth in the Upper
Awash River basin compared to the middle Abay River basin.
Description
Keywords
Inter-Basin Groundwater Transfer, Numerical Groundwater Modeling, TAGSAC, Middle Abay River Basin, Upper Awash River Basin, Ethiopia