Transcription
GroundwaterResource DirectedMeasures ManualRoger Parsons& Johan WentzelGroundwater Resource Directed Measures ManualTT 299/07Water Research Commission
SETTING RESOURCE DIRECTED MEASURES (RDM)FOR GROUNDWATER: A PILOT STUDYROGER PARSONSParsons and AssociatesJOHAN WENTZELDepartment of Water Affairs and ForestryWRC Report No TT 299/07APRIL 2007
Obtainable fromWater Research CommissionPrivate Bag X03Gezina0031The publication of this report emanates from a project entitled Setting Resource DirectedMeasures (RDM) for Groundwater (WRC project no K5/1427).DISCLAIMERThis report has been reviewed by the Water Research Commission (WRC) and approvedfor publication. Approval does not signify that the contents necessarily reflect the viewsand policies of the WRC, nor does mention of trade names or commercial productsconstitute endorsement or recommendation for useISBN 978-1-77005-510-0Printed in the Republic of South Africa
ContentsTABLE OF CONTENTSTable of ContentsAcknowledgementsList of AbbreviationsUnits of MeasurementGlossary1. INTRODUCTION. 11.11.21.31.4Preamble. 1Purpose of this manual . 1Structure of manual . 1Some useful references. 22. NATIONAL WATER ACT. 32.12.22.32.42.52.62.72.8Preamble. 3Foundations of water management in South Africa. 3Fundamental principles of water management in South Africa. 4Protection of water resources . 5Water use. 7Management and monitoring . 9In summary. 9Some useful references. 93. RESOURCE DIRECTED MEASURES . 103.1Overall process. 103.2Assumptions related to GRDM . 113.3Steps in undertaking a GRDM assessment . 123.3.1Preparatory phase . 123.3.2Description of study area. 133.3.3.Delineation of units . 133.3.4Resource Classification . 143.3.5Quantification of the Reserve. 153.3.6Setting Resource Quality Objectives. 163.3.7Review. 173.4Post-GRDM assessment activities . 173.4.1Implementing Resource Quality Objectives . 173.4.2GRDM-driven monitoring. 183.4.3Allocation . 193.5Responsibilities of stakeholders within DWAF . 203.6In summary. 203.7Some useful references. 21March 2006iii
Contents4. LEVELS OF GRDM DETERMINATION. 224.14.24.34.44.5Introduction . 22Guides for setting the level of GRDM determination . 23Recommended procedure. 26In summary. 27Some useful references. 275. UNDERSTANDING LINKAGES TO OTHER COMPONENTS OF RDM . 285.15.25.35.45.55.6Preamble. 28The role of groundwater in addressing basic human needs . 28Groundwater-dependent ecosystems. 28The role of groundwater in supporting other components of RDM. 31In summary. 33Some useful references. 336. PREPARATORY PHASE. 366.16.26.36.4Responsibility. 36Approach . 36Key outcomes. 37In summary. 387. DESCRIPTION OF STUDY AREA. 397.17.27.37.47.57.6Preamble. 39Data sources . 39Report structure . 41Key outcomes. 41In summary. 43Some useful references. 438. DELINEATION OF RESOURCE UNITS . 458.1Preamble. 458.2Significant water resources . 458.3Previous terminology . 468.4Delineation of resource unit . 478.4.1Primary delineation . 478.4.2Secondary delineation . 478.4.3Tertiary delineation . 488.4.4Physical criteria . 488.4.5Management criteria. 488.4.6Functional criteria . 498.5Key outcomes. 498.6In summary. 528.7Some useful references. 52March 2006iv
Contents9. RESOURCE CLASSIFICATION . 549.1Preamble. 549.2Present status categorisation procedure. 569.2.1Introduction . 569.2.2Limits of sustainability. 569.2.3Defining stress. 579.2.4General Categorisation. 589.3.Water resource categorisation . 619.4Key outcomes. 629.5In summary. 629.6Some useful references. 6210. QUANTIFICATION OF THE RESERVE . 6410.1 Groundwater component of the Reserve. 6410.2 Some terminology issues. 6410.3 Quantification process. 6410.3.1Recharge. 6510.3.2Groundwater inflows and outflows . 6710.3.3Basic human needs . 6710.3.4Groundwater contribution to baseflow. 6710.4 Key outcomes. 6910.5 In summary. 6910.6 Some useful references. 6911. RESOURCE QUALITY OBJECTIVES. rpose of resource quality objectives. 72What are Resource Quality Objectives . 73Setting Resource Quality Objectives. 73Types of groundwater RQOs. 74Considerations in setting RQOs . 74Format of RQOs . 75Procedure for setting RQOs . 75Examples of groundwater RQOs. 76Key outcomes. 77In summary. 77Some useful references. 7712. METHODS, TOOLS AND DATA. 7812.1 Quantifying recharge. 7812.1.1Recharge maps . 7812.1.2Expert opinion . 7912.1.3Chloride mass balance method. 8012.1.4EARTH model. 8012.1.5Cumulative rainfall departure method. 8112.1.6Saturated volume fluctuation method . 8112.1.7Isotopes. 82March 2006v
Contents12.1.8Numerical groundwater flow models. 8312.2 Quantifying other inflows and outflows. 8312.3 Quantifying the groundwater contribution to baseflow . 8412.3.1Baseflow maps . 8412.3.2Herold method of baseflow separation. 8412.3.3Rainfall-runoff modelling . 8612.3.4Darcy’s Law . 8612.3.5Numerical groundwater flow models. 8712.3.6Low maintenance flows . 8712.4 Resource quality objectives. 8712.4.1Delineation of protection or exclusion zones. 8712.4.2Calculating the radius of influence of a borehole . 8912.4.3Predicting drawdown as a result of abstraction. 8912.4.4 Estimating allowable rates of abstraction. 8912.5 Some useful references. 9113. CHALLENGES AHEAD. 9513.113.213.313.413.513.6Data . 95Monitoring. 95Integration . 95Methodologies. 96Definitions. 97Beyond GRDM . 9714. E10 CATCHMENT PILOT STUDY. 9814.1 Preparatory Phase. 9814.2 Description of Study Area. 9814.2.1Background Information . 9814.2.2Physiography and Climate . 9914.2.3 Geology . 9914.2.4 Geohydrology. 9914.3 Delineation of Units . 10014.4 Resource Classification . 10214.5 Quantification off the Reserve . 10414.6 Resource Quality Objectives. 10614.7 References . 108March 2006vi
AcknowledgementsACKNOWLEDGEMENTSParsons and Associates Specialist Groundwater Consultants, in collaboration with theDepartment of Water Affairs and Forestry (DWAF), were awarded a solicited research projectby the Water Research Commission (WRC) to implement and test methodologies fordetermining the groundwater component of Resource Directed Measures (RDM) that weredocumented by Xu et al. (2003). The objectives of the research project were: To review and implement methods developed to set RDM for groundwater through anappropriate case study.To refine and adapt methods as a result of lessons learnt during the pilot study.To align methods with other components of RDM (e.g. estuaries, rivers and wetlands).A guideline document and accompanying software were to be produced by the project. Theguideline document was to be submitted to DWAF so the methods could be readily andproperly implemented during future RDM assessments.Subsequent to being awarded the project, FETWater identified an urgent need to implement atraining program to improve skills within DWAF relating to RDM, with groundwater beingidentified as one of the areas requiring attention. Training was required before this researchproject was to be completed. As a result, a manual was produced for the FETWater Trainingand which relied heavily on work undertaken as part of the WRC research project. Likewise,the WRC rese
A guideline document and accompanying software were to be produced by the project. The guideline document was to be submitted to DWAF so the methods could be readily and properly implemented during future RDM assessments. Subsequent to being awarded the proje
