WORK PLANS - Laserfiche WebLink

Home Browse Search

MONITORING WELL STANDARDS INTRODUCTION Ground water rnonttoring wells are principally used for obsurvi.ng ground water levels and flt3w conditions, obtaining samples for determining ground water quality, and for evaluating hydraulic properties of water- bearing strata. Monitoring wells are sometimes referred to as "obscrvatiuri The quality of water intercepted by a monitoring well can range from drinking w.1Wr m highly pot kuLed water. In c.C}ntrasl,prod aetion Or'WUWr wells"are usually designed to nbtairt wales from productive zones eontailliag goDd-quality water. The SLTe4:.a or perforated section of a ronitoring well usuarIiy extends only a short length to obtain v,raier from, nr to monitor conditions within, an individual water-bearing unit or 70ne Water wells,ar(.often designed to nbtain water from multiple water-bearing strati. MEIIDngh there are usually clifferenc tietween the design and function of monitoring wells and water wells,water wells sornetim+Fs are usW a<1; Inonitoting wells,and vic tc versa, I Monitoring wells, along with other types of wells, can provide a pathway for the movcmc:nt ol`poor-quality umt.er, pollutants, and contaminants. Because monitoring wells are often purpo&ely located in areas affect" by pollutants anti contaminants, they pose �tn cspcciai[y significant threat to ground water clua hiy if they are not properly constructed, altered, maintained, and destroyed. "she California Legislature amended the-California Water Cade in 1986 specifically to inclade requirements for monitoring well standards. Monitoring wells wCrC previousiv assumed by the Department to be c;avc:rcd by she collectivc term "well" in the law, History of Monitoring Wells Monitoring wtrlIs were first used mainly for.vrator bevel rrmeasurernent. The c wells were often referred to as piezortteten in I-aA erence (0 tht, piezorricLric surface" of ground water- In recent years, the term nplezorrictric surface" is nftea replaced by"po ten tionictric surface" However, the term "piezometee i.ystilt somr-1jmes used for monitoring wells installed only for water level measurement. Many water level monitoring wells con-structed in the feast were relatively large in dixrriLier in comparison to today's monitoring wells. Wells up to 10-inches in diimclor were ofuan constructed to accommodate various mranq of water lev�l including Floats for mechanically-operated, continuous water level recorders. Many inactive water wells that could aca)mrnodate mechanical water level r=raing t�quipmw were used as monitoring wells. Modern electronic water level measuring and recording devices rtow allow for sruall-diameter water-kveI monitoring wells. Some continuous water-level measurement devices can be used in wells less than Z-inches ire iri5ide diame#er. The use of rnonitoririg wells fnr ground water sampling for chcmica1 3nalysN la as increased signfc:antly in the, past twu dccadt's. The Following factgrs have all served uo increase the frequency and scepo of ground water quality investigations and She nurmber of monitoring wells wnstructed: I