Integrated assessment of climate change adaptation options for water resources management using participatory and hydrological modelling approaches

Climate change adaptation (CCA) is a vital strategy for river basin water management which binds together environmental, agricultural and human water requirements in an uncertain future climate. Policy makers face a difficult task balancing demand and supply for conflicting water requirements, especially to justify present day economic costs for future benefits, like in CCA. No-regret adaptation options, applicable in both, current and future uncertain conditions, provide a way of dealing with these issues. However, determination of such options needs to be based on an integrated assessment of hydrologic, environmental, social, economic and institutional characteristics to be suitable in the future. Here, a three step process for determining no- regret options is presented, having been applied to the Kangsabati River basin in India. Firstly a participatory approach is used to identify potential CCA options, followed by a Multi Criteria Analysis (MCA) to determine the no- regret and suitability characteristics for the region. This approach was replicated at three levels; community, district and state (sub-national), targeting different stakeholders. Finally, hydrological modeling using Water Evaluation And Planning (WEAP) model, of the high ranking adaptation options show the expected efficacy in hydrologic terms. MCA generated no-regret options show importance of currently promoted soil and water conservation measures, like afforestation and check dams and the need for future focus on cropping pattern change. Evaluation criteria important to different stakeholders were also determined in the process, a valuable by-product useful for future water management. Present and future scenario based modelling of CCA options provides comparability in terms of suitability, scale of impacts and costs. Such assessments can be valuable tool-set for policymakers to make evidence based decisions on choice of adaptation measures and their spatio- temporal applications to improve water availability in an uncertain climate

Integrated assessment of no-regret climate change adaptation options for reservoir catchment and command areas

The need for credible, salient and legitimate climate change adaptation options in the water sector, which target location specific adaptation requirements, is well recognized. In developing countries, the low-hanging fruit; no-regret options, should be identified with stakeholders and assessed against future changes in water availability and demand, for comparing effectiveness and robustness. Such integrated basin-scale assessments, including reservoir catchment and command areas, can suitably inform adaptation decision-making. In this study, we integrate participatory and modelling approaches for evaluation of reservoir catchment and command area no-regret options addressing water availability and demand in the Kangsabati river basin. Through multi-level stakeholder workshops we identify and prioritize options, followed by evaluation of two reservoir catchment options; check dams and increasing forest cover and three reservoir command options; changing cropping pattern, traditional ponds and waste water reuse, using the Water Evaluation And Planning (WEAP) model. We use four high resolution (~25 km) regional climate model simulations of future climatic factors, along with non-climatic factors affecting water demand, for forcing WEAP. We find that options have varied ability in addressing adaptation requirements. Amongst catchment options, increasing forest cover addresses adaptation requirements more suitably than check dams, while in the command areas we observe mixed abilities of options, leading to the inference that combining complementary options may be a more useful strategy. We conclude by discussing our experiences with this approach in a developing country context, in terms of benefits, limitations, lessons learnt and future research directions

Sediment Transport Model for a Surface Irrigation System

Controlling irrigation-induced soil erosion is one of the important issues of irrigation management and surface water impairment. Irrigation models are useful in managing the irrigation and the associated ill effects on agricultural environment. In this paper, a physically based surface irrigation model was developed to predict sediment transport in irrigated furrows by integrating an irrigation hydraulic model with a quasi-steady state sediment transport model to predict sediment load in furrow irrigation. The irrigation hydraulic model simulates flow in a furrow irrigation system using the analytically solved zero-inertial overland flow equations and 1D-Green-Ampt, 2D-Fok, and Kostiakov-Lewis infiltration equations. Performance of the sediment transport model was evaluated for bare and cropped furrow fields. The results indicated that the sediment transport model can predict the initial sediment rate adequately, but the simulated sediment rate was less accurate for the later part of the irrigation event. Sensitivity analysis of the parameters of the sediment module showed that the soil erodibility coefficient was the most influential parameter for determining sediment load in furrow irrigation. The developed modeling tool can be used as a water management tool for mitigating sediment loss from the surface irrigated fields

Tillage and nutrient management influence net global warming potential and greenhouse gas intensity in soybean-wheat cropping system

207-214Conservation tillage has proven advantageous in improving soil health and productivity. However, the greenhouse gases (GHGs) emission and intensity from different conservation tillage and nutrient management systems under Indian conditions are less understood. Therefore, here, we compared the effect of tillage and nutrient management on GHGs emissions, net global warming potential (NGWP), and greenhouse gas intensity (GHGI) from a field experiment under five years in a soybean-wheat cropping system in the Vertisols. The tillage treatments comprised of reduced tillage (RT) and no tillage (NT). The three nutrient management treatments included application of 100% NPK (T1), 100% NPK + 1.0 Mg FYM-C ha-1 (T2), 100% NPK +2.0 Mg FYM-C ha-1 (T3). The results showed significantly higher SOC sequestration under NT (1388 kg ha-1 yr-1) followed byRT (1134 kg ha-1 yr-1) with application of FYM (2.0 Mg C ha-1) (T3) every year. Across tillage, integrated nutrient management(T2 and T3) lowered NGWP and GHGI compared to NPK (T1). The GHGI of NT system was less by 33% compared to RT. The results suggest that GHGs mitigation and sustained food production in the soybean-wheat system can be achieved in NT and RT with integrated use of organic and inorganic fertilizer as the major component of nutrient management