Présentations Colloques

Oral Presentation
4.01
Session 4.01: Innovative economic instruments and institutions for achieving sustained groundwater use. Integrated socio-economic and biophysical modeling for groundwater and conjunctive use management
Parker Timothy K.
The New Sustainable Groundwater Management Act in California
California’s Sustainable Groundwater Management Act (SGMA) became effective on January 2015, a landmark new law finally regulating groundwater in a state that produces 50 percent of the fruits, nuts and vegetables in the USA and is the 7th largest global economy. Historic drought, wells drying up and many more being drilled, along with increasing land subsidence helped pass the new law. SGMA requires that 127 of California’s 515 groundwater basins, considered medium- and high-priority, do the following- (1) form Groundwater Sustainability Agencies (GSAs) to completely cover all priority basins by June 2017, (2) develop Groundwater Sustainability Plans (GSPs) by January 2020 for critically overdrafted basins and January 2022 for remaining priority basins, and (3) become sustainably managed within 20 years of GSP adoption. Sustainable groundwater management is defined as the use and management of groundwater in 50-year planning without causing undesirable results. Six sustainability indicators are defined as undesirable results- (1) chronic lowering of groundwater levels, (2) reduction of groundwater storage, (3) seawater intrusion, (4) water quality degradation, (5) land subsidence that substantially interferes with surface land uses, (6) depletions of interconnected surface water, adverse impacts on beneficial uses of surface water. Local agencies that supply or manage water, or have land use authority are eligible to form GSAs, which must develop and manage to measurable objectives and minimum thresholds for the six indicators in a groundwater basin. SGMA also defines “sustainable yield” as the maximum quantity of water, calculated over a base period representative of long-term conditions in the basin and including any temporary surplus, that can be withdrawn annually from a groundwater supply without causing an undesirable result. Currently, GSA formation is taking place in many basins in the state, the most difficult part of SGMA. Regulations are being developed for GSP requirements, which will set the stage for what level of groundwater industry effort is required in the near and distant future to try and reach sustainability in the next quarter century in California.
USA