Integrated management of the Upper Mersey river basin using the SMILE object-oriented software system

This paper presents the application of the object-oriented framework SMILE to the management of flows and water quality in the Upper Mersey river catchment. The design river flows are those exceeded for 95% of the time, and are estimated applying alternative methods. The influence of compensation reservoirs, surface-water abstractions, and continuous discharges on low river flows is quantified. The annual licensed abstraction volumes are further reviewed. The monitored river water quality is classified using the River Ecosystem scheme. The compliance of the sewage treatment works and trade effluents with their discharge-consent limits is also assessed. The impact of effluents on the variation of river water quality is evaluated through Monte Carlo simulations at the discharge points. The points where the downstream water quality fails to comply with proposed River Quality Objectives are identified. The consent limits of the corresponding discharges are assessed, and changes to the BOD and total ammonia limits are suggested.