PROTECH simulations of QE2 and Wraysbury reservoirs using scenarios based on 1921-23, 1929, 1933-35 and 1943-44 droughts

Applying 48 scenarios to QE2 and Wraysbury Reservoir produced several clear results. 1. Drought-induced low reservoir water levels led to a decline in water quality caused by increase algal productivity. 2. A key factor behind this increase appears to be greater light availability rather than increased water temperature or nutrient concentrations. 3. RGF blockers types are the prevalent type of algae in the reservoir and they are persistent between years. 4. However, short-lived blooms of RGF penetrators can still occur, particularly in favourable light conditions