In this work we propose an ecological water quality model for a reservoir, based on first principles, to study the response of main phytoplankton groups (algae) to temperature rise due to global warming and different nutrient (phosphate) loading scenarios in the middle and long term. An optimal control problem is formulated to determine optimal combination of restoration strategies, including nutrient loading reduction through inflows remediation within a wetland and in-lake biorestoration techniques. The dynamic optimization problem is formulated within a simultaneous approach.