The Comaum-Caroline Prescribed Wells Area (PWA) is 400 km SE of Adelaide, and covers about 1900 square km. It consists of a coastal plain which rises to almost 70 m above sea level in the north of the area. In the far NE the Kanawinka Fault separates the plain from the Naracoorte Ranges. Unconfined and confined aquifers are both present and the main water resource is the unconfined aquifer (predominantly Gambier Limestone formation). Salinity ranges between 300 and 1000 mg/L. The PWA was proclaimed in 1986. There were originally 5 water management Sub-areas but there have been recent subdivisions to manage declining water levels. The total water allocation for the 1998/99 year was 78 093 ML, with an estimated water usage of 37 316 ML, about half the total allocation. The accuracy of this figure is debatable, as water use is estimated from crop figures supplied by the irrigator, and determined on the crop water use ratio system. Stock water use is only a minor contributor to the overall water budget (ie 1960 ML). There are currently 104 unconfined aquifer wells, measured quarterly in the water level monitoring network, and 49 wells in the unconfined aquifer salinity monitoring network. There are 10 confined aquifer water level and salinity monitoring wells. The networks have recently been increased and should meet the monitoring requirements. The impact that water use from one resource may have on another resource was considered in the following situations: - the impact of using surface water to artificially replenish the groundwater system. - the impact taking of groundwater from the unconfined aquifer may have on the confined aquifer. - the impact taking of groundwater from the confined aquifer may have on the unconfined aquifer. In the first scenario there is the potential for groundwater contamination to occur to the unconfined aquifer as a result of applying animal bi-products, agricultural chemicals and fertilisers in the southern portion of the PWA. In the second scenario the Nangwarry-Tarpeena area is heavily forested, resulting in very little recharge to the unconfined aquifer. This may also impact on the water resources of the confined aquifer. The third scenario is of limited relevance.