Soil Type: The suitability of soil is paramount. South Texas, particularly in areas like Duval County, often has sandy clay loam soil. Soils with higher clay content are preferred as they naturally hold water better than sandy soils. Conducting soil tests or digging test pits can help determine soil suitability. If the soil is too permeable, you might need to either import clay or use a pond liner, which can be costly but necessary for water retention.

Topography:
The natural landscape will influence where you can feasibly build a pond. Ponds should ideally be located in areas where the topography allows for water collection, such as natural depressions or areas where a dam can be built across a valley. Upland sites are often better than lowlands or marshes because they generally have a higher water table and are easier to excavate. However, avoid areas prone to flooding or excessive runoff that could lead to erosion or sedimentation.

Water Source:
The availability of water is crucial. If the pond is to be primarily fed by surface runoff, ensure that the drainage area is adequate to maintain water levels during dry spells but not so large that it causes excessive overflow or sediment accumulation. For ponds in South Texas, considering the semi-arid climate, it’s also vital to evaluate groundwater availability or whether the pond can be maintained with well water if necessary.