Final answer:
Development affects water table and local wells, potentially impacting riparian ecosystems and necessitating an evaluation of ecological costs and benefits.
Step-by-step explanation:
The question pertains to the environmental impact that a new housing development may have on the local water table, private wells, and river water levels. Since the development plans to extract groundwater through multiple wells, this will likely lead to a decline in the water table, potentially affecting nearby wells by lowering the water levels available for use—known as creating a cone of depression. The ecological balance, including the health of the riparian ecosystem, is dependent on maintaining current water levels. Moreover, the threshold level of land drainage that would require screening to inform development is a complex decision involving rigorous evaluation of costs and benefits, which could relate to factors such as extent of habitat alteration, or pre-defined thresholds such as those mentioned in relation to fire regimes affecting scherophyll vegetation diversity.