Transcript groundwater
FAO-UN Investment Days 2014 GLOBAL WATER PARTNERSHIP GROUNDWATER GOVERNANCE Priorities to Sustain a Critical Resource Prof Dr Stephen Foster Global Water Partnership–Senior Adviser International Association of Hydogeologists–Past President Global Water Partnership GROUNDWATER – A GLOBAL OVERVIEW • Strategic Importance & Sustainability Concerns • Intimate Relation with Irrigated Agriculture • Strengthening Groundwater Governance • Specific & Urgent Investment Priorities GROUNDWATER – NATURAL DISCHARGE fundamental role in sustaining aquatic ecosystems FRESHWATER DISCHARGE TO COASTAL LAGOONS NATURAL BASEFLOW TO RIVER ECOSYSTEMS • groundwater – the ‘traditional role’ source of >50% (rural/urban) drinking water-supply GROUNDWATER IRRIGATION USE the global boom • groundwater extraction increased 300% in 50 years (1960-2010) • massive growth of irrigation waterwells in some regions facilitated by government (energy subsidies/construction loans/crop guarantees) REGION GLOBAL TOTAL GROUNDWATER IRRIGATION AREA Mha total GROUNDWATER VOLUME USED km3/a propn 112.9 38% 545 43% South Asia(India/Pakistan) 48.3 57% 262 57% East Asia (China) 19.3 29% 57 34% South-East Asia 1.0 5% 3 6% 12.9 43% 87 44% Latin America 2.5 18% 8 19% Sub-Saharan Africa 0.4 6% 2 7% Mid-East & North Africa (Siebert et al, 2010 for FAO-UN) GROUNDWATER DEPLETION – NEGATIVE EXTERNALITIES onset and impact varies widely with aquifer type • energy consumption • carbon footprint • contribution sea-level rise GROUNDWATER DEVELOPMENT STAGES environmental and socio-economic impacts GROUNDWATER RESOURCE DEPLETION a widespread and accelerating phenomenon • ~15% of existing staple grain irrigated with non-renewable groundwater resources • mining of fossil groundwater during 1955-2005 contributed 10-15 mm to sea-level rise Konikow, 2011 GROUNDWATER – A GLOBAL OVERVIEW • Strategic Importance & Sustainability Concerns • Intimate Relation with Irrigated Agriculture • Strengthening Groundwater Governance • Specific & Urgent Investment Priorities IRRIGATED AGRICULTURE & GROUNDWATER RESOURCES an intimate multi-facetted relationship • irrigated land-use practices are a major influence on groundwater recharge • groundwater salinisation is a serious and complex threat associated with irrigated agriculture in more arid climates • groundwater very popular with farmers (self control/direct local access/drought secure) irrigated agriculture is the major consumer of groundwater resources • agricultural land-use is a ‘leaky activity’ and a major source of diffuse groundwater pollution • scientific tools now available to characterise the dynamics of these interactions with confidence and in detail SURFACE-WATER IRRIGATION MANAGEMENT effect on groundwater recharge rates and quality permeable soil profiles quality cannot be divorced from quantity PERU-ICA VALLEY : ASPARAGUS PRODUCTION sustainability threatened by decreasing recharge • relatively stable groundwater abstraction over past 50 years • recent falling water-table due to abandoning spate/flood irrigation • modernisation of irrigated cropping with increasing consumptive use – urgently needs supporting by managed recharge measures Ddddddddddd d Ddddddddddd PAKISTAN PUNJAB growing groundwater dependence for staple crop production but continuing long-run battle with the ‘salinity dragon’ semi-arid zone with diffuse groundwater recharge from annual monsoonal rainfall arid zone with fresh groundwater recharge primarily from riverbed and irrigation canal seepage – but freshwater salinity increasing due to salt fractionation in irrigated soils, extensive phreatic evaporation and use of deep irrigation waterwells GROUNDWATER SYSTEM SALINISATION factors entering into aquifer salt balances in arid areas return waters varying salinity freshwater recharge m m m other factors in aquifer salt balances : • drawing-in from phreatic and vadose zone salinity • mobilisation via deep waterwells • inflow from saline formations nutrient leaching DIFFUSE POLLUTION FROM AGRICULTURAL LAND-USE pesticide mobility Cryptosporidium hazard saline returns cultivation of permeable soils is a ‘leaky activity’ – farmers cultivating land also (accidentally) harvest groundwater GROUNDWATER – A GLOBAL OVERVIEW • Strategic Importance & Sustainability Concerns • Intimate Relation with Irrigated Agriculture • Strengthening Groundwater Governance • Specific & Urgent Investment Priorities historically groundwater resources have largely been ‘abandoned to chance’ in face of agricultural development ‘business-as-usual’ will result in further irreversible degradation and growing conflict government role must transform from ‘promoter of shortterm development’ to ‘long-term resource guardian’ widespread need to strengthen governance provisions : building effective institutions creating an adequate base making essential linkages aligning financial incentives implementing management plans promote more integrated and sustainable policy with appropriate monitoring and assessment as basis for adaptive management to cope with global change GROUNDWATER GOVERNANCE & MANAGEMENT size matters – understand context evident governance provisions/ management approaches must to a degree be context specific and take account of : HYDROGEOLOGICAL SETTING • Groundwater Resource Renewability • Susceptibility to Degradation • Scale of Aquifer Storage • Connectivity with Surface Water POLITICAL ECONOMY OF RESOURCE • Propn of Population Using Waterwells • Number of Abstraction Points • Economic Significance of Resource Use • Capacity of Water Resources Agency ‘one size cannot fit all’ Groundwater Resource Management TAILOR TO CONTEXT GROUNDWATER – A GLOBAL OVERVIEW • Strategic Importance & Sustainability Concerns • Intimate Relation with Irrigated Agriculture • Strengthening Groundwater Governance • Specific & Urgent Investment Priorities CONJUNCTIVE USE FOR IRRIGATED AGRICULTURE managed evolution from spontaneous to planned development SPONTANEOUS waterlogging & salinization risk if water-table shallow PLANNED groundwater depletion risk GROUNDWATER & IMPROVED IRRIGATION TECHNOLOGY ‘irrigation-water efficiency’ a misleading term • ‘irrigation-water efficiency’ improved 40% to 80% (230 mm for wheat crop) • but ‘real water-resource savings’ (reductions in non-beneficial evaporation) only by 55 mm for crop (< 40 mm/a over entire land area) • most so-called ‘water losses’ were in fact irrigation returns to groundwater • modifying monsoon rice cultivation in Indian Punjab more successful – delayed-planting generated reduction in non-beneficial evaporation of 90-100 mm/a for rice crop (80-90 mm/a over entire land area) DEMAND MANAGEMENT • align fiscal incentives in support of resource sustainability • regulate waterwell extraction and consumptive use (construction grants, electricity subsidies, crop guarantee prices) (‘smarter approaches’ to controlling waterwell use) (focus on reduction of non-beneficial evapotranspiration) (innovative use of financial nexus with energy provision/charging) SUPPLY ENHANCEMENT reward land stewardship that augments recharge promote productive land-use that protects groundwater quality INSTITUTIONAL FOUNDATION • strengthen government agency capacity to administer resource • integrate responsibility for resource conservation and quality protection • establish essential linkages with dependent sectors/activities nuture stakeholder participation via financial and regulatory support improve groundwater system and soil-water accounting (including groundwater level/quality status monitoring – with telemetry to provide basis for adaptive management) • finance revenue cost of monitoring promote and optimise conjunctive use with canal-water in alluvial systems (understanding physical connectivity (from selective levying of a resource fee) and overcoming socioeconomic impediments) FAO-UN Investment Days 2014 GLOBAL WATER PARTNERSHIP GROUNDWATER GOVERNANCE Priorities to Sustain a Critical Resource Prof Dr Stephen Foster Global Water Partnership–Senior Adviser International Association of Hydogeologists–Past President Global Water Partnership