Eco-hydrological assessment of water catchments: A requisite water management strategy

The research was applied at western flank of the Nigerian Eastern Littoral Hydrological Area, where Base-flow and stream-flow evolved from coal field and karst environment, respectively. Abiotic as well as biotic factors and relationship with water supply prompted the research. To protect water resources from these factors, knowledge of the evolution is requisite. Such was ascertained using aeromagnetic, radiometric, resistivity and hydro-geologic mapping. Consequently, linear features in NW—SE and NE—SW orientations were identified and verified as respective hydrologic and non-hydrologic structures. Depth to the hydrologic structures ranged from 1.3 to 3.3 m at upstream; thus, shallow and interfaced for emergence of stream-flow. Even so, groundwater occurrence was supported towards downstream at depth between 21 and 77 m. Moreover, the hydrologic structures guided dispersions of solute chemicals suspected as Fe 2 O 3 / carbonates-related ions being detected at resistivity between 0.003ῼm and 2ῼm. These chemicals inflict both adverse and favorable effects on the ecosystem through the water supply. In terms of adverse effect, the chemicals alter the water resources qualities; hence, can compromise growth of plants, particularly in period of soil drying following the general global warming. This prediction follows fact that residual solutes concentrate in soils (building salinity poison) when the soil water escapes into vapor by vegetation-induced Evapo-Transpiration. Conversely, the eco-friendly vegetation is nourished by the ions after dilution to nutrient level during soil saturation. These contrasts pose water management challenge amid river bank erosion/ e-flow deterioration; needing mutual approach in water policy decisions; like, encouraging riparian vegetation but minimizing phreatophytes.