Non-renewable groundwater resources: a ... - unesdoc - Unesco

NON-RENEWABLE GROUNDWATER RESOURCESAn exhaustive checking of the monitoring data will take place periodically. Duringthe three first years, it will be done every year, and from then on, a frequency will be setaccording to the results obtained in the three first years.Monitoring results up to December 2001The exploitation of the Monturaqui – Negrillar – Tilopozo aquifer began in the mid-1990s.Before implementing the Early Alert Plan (PAT–MNT) the two mining companies of thecountry extracted over 47 million cubic meters (MCM) of groundwater from the Monturaquiand Negrillar sectors by 31 December 2000.During 2001, the pumping rates from the Monturaqui well field increased so that by the endof 2001 the accumulated volume of extracted water from Monturaqui sector itself exceededa total of 47 MCM. The pumping rates from the Negrillar sector continued at the same ratereaching a total extraction in excess of 30 MCM by the end of 2001.These accumulated volumes were used to estimate the maximum future reduction ofthe aquifer’s flow under the PAT–MNT. Under this policy the maximum reduction forecastedfor the future of the aquifer’s flow corresponds to approximately 0.8%. The permitted limitcorresponds to 6%.SummaryChile has implemented a plan for adaptively managing its intensively used aquifers with the goalof long-term sustainability. This is challenging under its present legal system that gives waterusers rights to the water they use in perpetuity, but it is meeting this challenge with the aid ofan Early Alert Plan. This Plan requires periodic monitoring of aquifer conditions, and the issuingof permits for withdrawals of groundwater that specify reduced extraction rates should conditionsso warrant. Monitoring is an absolutely essential component of this adaptive managementstrategy.92