Table 5.14 (continued) Maximal and Entry-level or Residual risk assessment precommissioning residual simplified assessment (operational) risk assessment without surface events, to allow Preventive See Section 6.1 waterlogging groundwater mound to • measures concerning subside Relocate infiltration site • clogging and redesign separation Where real-time • Install management distances between recharge adaptive management • is required, use overflow facilities and recovery diversion feedback control locations, and between Restrict • to prevent systems (to change potentially polluting land volume and rate excessive pumping rates or shut uses and waste of recharge to recharge down flow) and management practices in periods heads or telemetered messaging the area and the managed appropriate to the volumes systems aquifer recharge operation local conditions • Construct piezometers and (eg annual, • observation wells to allow monthly, daily) event early warning and assist in Drill, slot or rip • use of model calibration subsurface pumps semipermeable for layers to Increase drying time • allow in basins or galleries infiltration between infiltration or galleries Validation Monitor soil moisture, • monitoring suction and piezometric levels in unsaturated zone beneath basin and gallery, to discriminate between causes of any detected reduction in • infiltration rate Monitor function of M • connected ecosystem if warranted by the level of impact t a b
Table 5.14 (continued) Entry-level or simplified assessment Maximal and precommissioning residual risk assessment Residual risk assessment (operational) Preventive measures • Install overflow diversion to prevent excessive recharge heads or volumes • use of pumps for • See Section 6.1 concerning clogging management • Restrict volume and rate of recharge to periods appropriate to the local conditions (eg annual, monthly, daily) • Drill, slot or rip subsurface semipermeable layers to allow infiltration without surface waterlogging • Relocate infiltration site and redesign separation distances between recharge facilities and recovery locations, and between potentially polluting land uses and waste management practices in the area and the managed aquifer recharge operation • Construct piezometers and observation wells to allow early warning and assist in model calibration • Increase drying time in basins or galleries between infiltration events, to allow groundwater mound to subside • Where real-time adaptive management is required, use feedback control systems (to change pumping rates or shut down flow) and telemetered messaging systems Validation monitoring • or galleries • Monitor soil moisture, suction and piezometric levels in unsaturated zone beneath basin and gallery, to discriminate between causes of any detected reduction in infiltration rate • Monitor function of connected ecosystem if warranted by the level of impact event a M t b
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