Hydrogeological and Hydrological assessment
- Review restoration strategies employed in different hydrogeological settings
- Identify hydrogeological and hydrological constraints on restoration strategies
- Review hydrological restoration strategies – with reference to flood alleviation and bankside storage
- Baseline data collection
- Fieldwork
- Investigate the groundwater interactions between superficial deposits, the underlying bedrock and the adjacent surface water and wetland systems.
- Determine the hydrological and hydrogeological requirements of the proposed restoration
Restoration may involve a combination of infilling and the creation of open waterbodies and wetland. Rainfall recharge, evapotranspiration, interaction with the groundwater system and surface water inflows and outflows all contribute to the range in water levels within a restoration site and define its characteristics. Many of these factors can be influenced by the careful design and engineering of features such as catchment area, topography, lake depth/width ratio, continuity with the groundwater system and outfall design.
Modification of the local aquifer, which will result from sub-watertable mineral extraction, has the potential to impact upon groundwater flow patterns and hence surface water and groundwater resources. Fill material used in restorations often comprises overburden, quarry fines and imported waste material, the physical and chemical properties of which may have a significant effect on ground and surface water quality and flows.
In many settings knowledge of the local groundwater and surface water interactions is essential to understanding the impact of a proposed restoration scheme.
The removal of mineral and ‘replacement’ by water may modify the flooding characteristics of nearby watercourses. These effects may potentially be either beneficial or detrimental.
The creation of waterbodies/voids adjacent to rivers can be exploited to beneficial effect by use as bank-side storage: water is pumped from the river to the waterbody during the winter months when river levels are high and can be drawn-off in the summer months for public (or private) water supply and/or to ameliorate low river flows.