Since 1987 APEM have been undertaking environmental modelling in water quality, sediment and ecology through a wide range of studies within the UK. These include projects in highly polluted artificial docks, drinking water reservoirs, rivers and estuaries.

Water Quality Modelling

APEM base water quality modelling studies on a variety of statistical approaches. An example is stepwise regression analysis, which was used to develop simple water quality models to help estimate oxygen injection requirements in the Manchester Ship Canal as early as 1990. These were later refined into multivariate mass flux models which proved to be remarkably accurate and are still in use today in a refined format as part of the on-going active feedback management of the MSC oxygenation project.

Another example is the mass flux model approach, which was successfully used on a range of other studies including Cavendish Dock, Barrow-in Furness, when evaluating the impacts of storm sewage inputs. This methodology was also used in a high profile legal case where APEM were required to estimate the likely quantity of sewage discharged to an estuary following a mechanical failure at a treatment works using receiving water flow and chemical data. Mass flux analysis for aeration requirements has also been undertaken for a number of artificial water bodies including a design, build and operate scheme at the Riverside, Market Dock, South Shields together with survey and design schemes for water supply reservoirs in the South West of England

Sediment Modelling

APEM are also routinely involved in data collection and calibration exercises for more sophisticated modelling projects. For example, we were contracted as water quality specialists for an EIA of the proposed Ribble Link, connecting the Lancaster Canal with the national inland waterway network via the River Ribble. Intensive monitoring was undertaken including 24hr Dry Weather Flow sampling for analysis of nutrients, suspended solids and BOD to provide data for a sophisticated MIKE 11 model. In addition sediment samples were taken and BOD / SOD analysis undertaken to help predict sediment behaviour within the MIKE 11 model. APEM were commissioned to provide expert environmental advice for a proposed link between the Leeds and Liverpool Canal and the Liverpool Docks.

Ecological Modelling

APEM's ecological modelling expertise centres around fish, invertebrates and algae. Since the early 1990's we have been developing simple life history survival models for both salmonids and coarse fish. These have been used in a variety of low flow studies such as the Hodder Sub-Catchment Fisheries and Macroinvertebrate Study, the River Lochy Water Abstraction Impact Study (Fisheries & Invertebrates), River Eden Ecological Studies, Impact of Flow Regulation on Fisheries of the River Dee and most recently the effects of Reservoir contribution and operation on the fish population of the River Tamar. The approach has also been successfully used in a number of pollution cases to estimate, for example, the loss to angling and spawning which has occurred as a consequence of juvenile fish kills.

Invertebrate modelling uses conventional industry packages (RIVPACS and LIFE scores), bespoke techniques such as cluster analysis including Primer and canonical analysis and a range of other multivariate techniques. APEM used these techniques in the detailed study of the Impact of the 1995-1996 Drought on Yorkshire Rivers and subsequently on the Hampshire Avon investigations into the impact of abstractions on low flows and hence the invertebrate community.

Algal modelling, to estimate potential and actual biomass production (as chlorophyll a), has been undertaken on a range of waterbodies from artificial docks to reservoirs and river systems. Examples include the National Dock Survey, Cavendish Dock, Barrow-in-Furness, Salford Quays, Manchester Ship Canal, Liverpool South Docks, Upper Tamar Lakes and the River Tamar.