Final answer:
Soil on a flood plain with a high groundwater table is often fertile and saturated, but poor drainage can result in darker and more anaerobic soil conditions. The ecosystem depends on the maintenance of the existing groundwater levels, which can be disrupted by increased groundwater withdrawal.
Step-by-step explanation:
Soil found on a flood plain with a high groundwater table is likely to be very fertile, as it is often enriched with sediments deposited by floods. These floodplain soils tend to have higher levels of organic matter due to the deposition of material during flooding events. However, these areas can also suffer from poor drainage, leading to soil that is more greyish, greenish-grey, or dark colored due to iron reduction and accumulation of organic matter in anoxic conditions. In any case, the soil will usually be highly saturated, which influences plant survival and requires certain adaptations.
Groundwater flow is greatly impacted by the presence of a high water table. Increased groundwater withdrawal for development can significantly affect this flow and water availability in nearby regions, potentially creating cones of depression around wells and lowering the water table, with negative impacts on local ecosystems.
It is crucial to maintain the current level of the water table to support the ecosystem that depends on it, as well as sustain other bodies of surface water such as rivers, which receive a constant inflow from groundwater below.