ASSESSMENT OF METHODS AND CONDITIONS TO LOCATE BOUNDARIES .2. ONE STRAIGHT RECHARGE BOUNDARY

A straight recharge boundary in an ideal aquifer is easily detected in the drawdown graph of an observation well. Two known and one proposed methods can be used to find the location and orientation of the recha rge boundary. This paper assesses their performance. Both the law of t imes and the method of inflection point overestimate the distance r(i) to the imaginary well when the ratio beta = r(i)/r(r) is smaller than 20. In this case, known methods also give incorrect estimates of aqui fer parameters. The proposed method gives directly the beta-value when it is higher than 20. For lower beta-values, a correction factor tran sforms the apparent beta-value into the correct beta-value. Two exampl es illustrate the quality of predictions by the known and proposed met hods. Two known and one proposed methods relative to impervious bounda ries are assessed in a companion paper.