REPORT NO. R-21.5 SALINlTY MANAGEMENT ALTERNATIVES FOR THE RECZINA DOAB, PUNJAB, PAKISTAN Voltline Five Predicting Future Tubewell Salinity Discharges G3t:y,&...~..,....... ................ ..R 7% ......... ... bL.......... LL,i<o.&..,9,2.%...... Muliainniad Aslain (Principal Irrigatioll Engineer, Salinity) JANUARY 1997 PAKISTAN NATIONAL PROGRAM INTERNATIONAL IRRICATION MANAGEMENT INSTITUTE LAHORE FOREWORD This report is one of eight volumes under the unibrclla title "Salinity Management Alternatives for the Rechna Doab, Punjab, Pakistan." The fundiiig for this effort has been provided by the Government of The Netherlands through the Royal Netherlands Embassy in Islamabad under the Phase I1 project, "Managing Irrigation for Environmentally Sustainable Agriculture in Pakistan." Between 1989-93, IIMI operated three field stations in Rechna Doab using Dutch phase I funding; much of this field data has been incorporated into this study. Rechna Doab, the ancient floodplain between the liavi and Chenab rivers covering a gross area of 2.9 Mlia, is one of the most intensively developed irrigated area within the countiy. With over a century of modern irrigation development, primarily by diversions from the Chenab River, agricultural productivity was continually bolstered. Then, some localities were beset with the threats of higher subsurface water levels and soil salinization. The public sector responded by implementing Salinity Control and Reclamation Projects (SCARPS) beginning in 1960. ,These projects, plus a huge increase in private tubewell development since 1980, have lowered subsurface water levels; however, the use of poor quality tubewell water, particularly in the center of the Doab, has resulted in secondaiy salinization. 'lXs study is an integrated attempt across both space and time to address the systems responsiveness to the abovementioned concerns. Vast amounts of data have been collected by public agencies in this study area since 1960. There are a number of agriculture census reports (1960, 1972, 1980 and 1990). Also, the Wat.cr and Power Dcvelopnient Authority (WAPDA) has done extensive investigations; their data were made available to IIMI through the General Management (Planning) and the SCARPs Monitoring Organization (SMO). In addition, WAPDA deputed an engineer half- time to participate in these studies who is knowledgeable on the Indus Basin Model Revised (see Volume Eight), which was used primarily to study the effect of groundwater balance constraints on cropping patterns. The planning for this study was done during January-March 1995. Then, spatial database manipulations using GIS tools were employed to provide the base stratifications leading to the selection of sample sites for IIMI's field campaigns during 1995, which were meant to corroborate, and in many instances update, the information already gathered from public sources. This included, in addition to structured farmer interviews, physical observations on the useable pumped water quality, soil salinity, surface soil texture, and cropping patterns. This integrated approach involves a synthesis of spatial modeling comprising drainage, salinity, and groundwater use constraints with a calibrated groundwater salinity model, a root zoiie surface and groundwater balance model, and production function models appropriate to the agroccology of the area. The output provides both suggestive and predictive links to the sust.ainability of irrigated agriculture in the Rechna Doab. Gaylord V. Skogerboe Director, Pakistan National Program International Irrigation Management Institute Table of Contents 1. INTRODUCTION .............................................................................................................. 1 A. Groundwater Geology ......................................................................................... 2 B . Aquifer Characteristics ......................................................................................... 5 C. Vertical Distribution of Salinity in Groundwater Reservoir ............................. 5 D . Tubewell Development a 1) SCARP Tubewells ...................................................................................... 6 2) Private Tubewells ...................................................................................... 12 - I1. COLLECTION OF INFORMATION ON SALINITY OF TUREWELL WATER A . Existing Groundwater Salinity Data Situation.................................................. 15 B . Field Measurements of Groundwater Salinity of Tubewell Water ................ 17 111. PREDICTING TEMPORAL VARIATIONS IN SALINITY OF TUBEWELL WATER A . Predictions on Individual Tubewells 1) Central Rechna Doab ............................................................................... 18 2) Lower Rechna Doab ................................................................................. 29 B. Predictions on Group of Tubewells .................................................................. 30 IV . ISSUES AND OPTIONS RELATED TO TUBEWELL IRRIGATION A . Issues 1) Inequitable and Unreliable Canal Water Distribution .......................... 36 2) Groundwater Quality ................................................................................ 36 3) Salt Balance ........................ :..................................................................... 37 4) Cropping Pattern Shift.............................................................................. 37 B . Options................................................................................................................. 37 1) Equitable and Reliable Water Distribution .......................................... 37 2) Skimming Well Technology...................................................................... 38 3) Revision of Water Allocations ................................................................. 38 4) Low-De1t.a Crops....................................................................................... 38 5) On Farm Water Management .................................................................. 38 6) Conjunctive Use ........................................................................................ 39 7) Farmer’s.. Awareness of Land Reclamation ............................................ 39 8) Monitoring of Salt Balance ....................................................................... 39 V. SYNTHESIS OF FINDINGS ......................................................................................... 40 A. General Findings ................................................................................................ 41 B. Model Study Findings 1) Central Doab: SCARP-I Tubewells ........................................................ 42 2) Lower Rechna: Satiana Pilot Project Tubewells .................................... 43 VI. SUMMARY..................................................................................................................... 43 r. VII. CONCLUSIONS AND RECOMMENDATIONS...................................................... 47 - REFERENCES ........................................................................................................................ 49 .. 11 List of Tables Table 1 Groundwater Quality Classification for Irrigation Use .................................... 16 Table 2 Water Quality Data for Selected SCARP-I Tubewells, Rechna Doab, Punjab, Pakistan (TDS, ppm) .................................................. 20 Table 3 Groundwater Model Input Data For SCARP-I Tubewells ............................. 21 Table 4 Water Quality Data for Selected Satiana Pilot Project Tubewells in the Rechna Doab, Punjab, Pakistan (TDS, ppm) ........................................ 29 Table 5 Water Quality Data for Group Simulation of Eight Tubewells of Satiana Pilot Project (TDS, ppm) ................................................................. 33 Table 6 Predicted Concentration of Pumped Groundwater for SCARP-I Tubewells in the Rechna Doab, Punjab, Pakistan (TDS, ppm) ........................................ 44 Table 7 Predicted Concentration of Pumped Groundwater for Satiana Pilot Project Wells, Rechna Doab, Punjab, Pakistan (TDS, ppm) ....................................... 44 Table 8 Salinity Concentration of Pumped Water During 1981 and 2010 for Discharges of 71, 43 and 7 Ips (TDS, ppm) ......................................................................... 44 c ... 111 List of Figures Figure 1 Depth of Bedrock across Rechna Doab ............................................................. 3 Figure 2 Geological Section A-A' in Rechna Doab ........................................................... 4 Figure 3 Location of Test Holes in Rechna Doab ............................................................. 7. .. Figure 4 Distribution of Groundwater Salinity in Fresh Water Zone with Depth for Rechna Doab ....................................................................................... 8 Figure 5 Distribution of Groundwater Salinity in Saline Water Zone with Depth for Rechna Doab ....................................................................................... 9 Figure 6 Private Tubewell Development in Lagar Distributary Command ................... 14 Figure 7 Private Tubewell Development in Mananwala Distributaiy Command ......... 14 Figure 8 Private.. Tubewell Density of sample watercourses of Mananwala Distributary.......................................................................................................... 14 Figure 9 Reclamation Scheme Area of