The conference ‘Toward Sustainable Groundwater in Agriculture’ (www.ag-groundwater.org) was held in San Francisco from 28-30 June 2016. Due to both a lack of groundwater resources management and consecutive years of severe droughts, overexploitation of groundwater resources is a major problem in California. Therefore, the Sustainable Groundwater Management Act (SGMA) was introduced, which creates a (stringent) framework for sustainable, local groundwater management. Good groundwater management will provide a buffer against drought and climate change, and contribute to reliable water supplies regardless of weather patterns. California’s water situation ran as a common thread through the conference, with a search for adaptation measures to make better use of the freshwater resources. Many of the problems in California are equivalent to the climate adaption measures that need to be taken to prevent freshwater shortages in the Netherlands. Besides KWR, also RIVM, Wageningen UR, Royal Haskoning-DHV, LEI and Deltares were represented.
In California, one is in an urgent search of freshwater sources to stop the depletion of groundwater resources. Quite some effort is put on increasing the groundwater recharge, by using both surface water and treated wastewater (‘recycled water’). Several presentations provided insights that are also relevant for the situation in the Netherlands; also we could put more effort on active recharge of our groundwater system. Although nitrate leaching from agricultural fields is predominantly on the agenda, surprisingly little attention is paid to the potential pollution of the groundwater with e.g. micropollutants. Important however, is not to solve the water quantity issue, while introducing problems with groundwater quality. A more thorough approach, integrating both water quantity and quality issues, will be required.
Such an integrated approach was presented by Koen Zuurbier, discussing whether freshwater storage in brackish-saline aquifers for irrigation water supply is a ‘bottomless pit’ or a ‘fountain of gold’. If done thoroughly, the latter is definitely true. I presented our work on matching the agricultural freshwater supply and demand, by using industrial and domestic treated wastewater for subsurface irrigation purposes. Our integrated approach, focusing on both water quantity and quality and bringing together all stakeholders (water boards, provinces, farmers, industries, drinking water companies), will hopefully result in a robust freshwater supply by better exploitation of the available resources.