Projects

Strathclyde Loch Bathing Water Study

RPS carried out an extensive Water Quality Study of the Strathclyde Loch on behalf of key stakeholders, Scottish Water, North Lanarkshire Council and SEPA.

Background

Water companies across England, Scotland and Wales are responsible for a number of reservoirs, rivers and watercourses. The accurate surveying, sampling and measure of water is important in understanding water catchments, water quality and pollution and for designing, building and verifying hydraulic models.

With OFWAT’s emphasis on improving water quality compliance and reducing pollution incidents over the AMP7 period, it is becoming increasingly important for water companies to understand water quality issues within their catchments. Working closely with our clients, we deliver results that both meet and exceed regulatory requirements and expectations. Strathclyde Loch is an artificial freshwater lake in Strathclyde Country Park, Lanarkshire. The Loch is adjacent to the River Clyde and is primarily fed by the South Calder Water. The Loch drains to the River Clyde via a regulated spill-over discharge point at 4 separate locations. The Water Sports Centre at the south-west end of the loch is regularly used for triathlon swimming events, including the Glasgow Commonwealth Games in 2014.

In 2017, RPS was commissioned to carry out an extensive data collection exercise as part of the Strathclyde Loch Bathing Water Study. Our activities included water quality sampling and flow monitoring, along with the collection of a range of meteorological, topographical and hydrographical data.

Challenge

RPS carried out an extensive Water Quality Study of the Strathclyde Loch on behalf of key stakeholders, Scottish Water, North Lanarkshire Council and SEPA.

The extent of the designated bathing water area within the Loch was unknown and as such, this study was undertaken to define the areas of the Loch that could comply with three sources of Water Quality targets:

The Water Framework Directive (WFD)
The Urban Pollution Manual (UPM) and
The Revised Bathing Water Directive (rBWD)

The objective of the project was to provide factual information on Strathclyde Loch and associated structures, such that the catchment network modelling team could construct and verify a water quality model which could then be used to understand how pollution propagates from upstream sources, through the loch and to design possible solutions to prevent this.

To support the modelling assessment, RPS conducted a comprehensive data collection exercise to extend and fill the gaps within the existing datasets and provide physical attributes of the water bodies.

Solution

To comply with the WFD classification scheme, and the rBWD, RPS collected and analysed data to determine percentile concentrations of the following determinands:

Amonia (NH3)
Biochemical Oxygen Demand (BOD)
Dissolved Oxygen (DO)
Soluble Reactive Phosphate (SRP)
Phytobenthos (Diatoms)
Intestinal Enterococci (IE)
Escherichia Coli (EC)

Over 6 months, we deployed a range of equipment and undertook testing across the loch and in the upstream watercourses, including:

Continuous flow surveys at river locations and loch outlets
Continuous WQ sonde deployment
Acoustic Doppler Current Profiler (ADCP) deployment
Weekly Spot Sampling at 7 loch and river locations with lab analysis
Deployment of 24 Auto-Samplers on floating pontoons within the loch
Release of Rhodamine Dye to watercourse and detection in river and loch

Benefit

The location of sampling points, within the loch and along the upstream river reach, presented a significant challenge on this project. We were required to carry out reactive sampling for 3 storm events and 2 dry weather events. Safe working methods were developed with the advance knowledge that access would be required under a range of weather and river conditions over several seasons.

By using multiple autosamplers mounted on pontoons within the loch, we were able to reduce risk in several ways. Our approach removed the H&S risk associated with the use of boats, allowing sampling to be carried out on dry land. Similarly, by mounting sensors on water-borne unmanned autonomous vehicles (UAV), we were able to carry out real-time detection of dye plumes. Combined with flow data and ADCP data, we were able to provide multiple data sets to build a detailed understanding of the hydrodynamics of the loch around the incoming watercourse.