| Aquifer recharge was estimated for six locations in southern New Jersey. The Darcian method was used with unsaturated zone sediment properties that were measured directly and predicted by multiple methods. This study shows that estimated recharge rates can be highly variable depending on the chosen technique. Measured hydraulic properties yielded reasonable recharge rates, although interpolation of measured data proved critical. Errors in measured field water contents required by the Darcian method also had a large effect on predicted recharge rates. Very slight variations in field water-content values can translate into order-of-magnitude differences in estimated recharge rates due to the highly nonlinear relationship between hydraulic conductivity and water content. While episodic recharge was observed in a uniform soil, significant layering appears to slow downward flow. This results in a more diffuse, less pulse-like wetting front and, therefore, less variable recharge over time. |
