Culvert Flow Gauging Structure - Ceredigion

The Mining Remediation Authority (MRA) is seeking a contractor to construct a flow monitoring structure at the outfall of a historic culvert. This culvert drains the dressing floor of a former mine site. The purpose of the structure is to enable accurate measurement of water flows entering a recently lined stream.

Following the application of concrete canvas to line the stream, water discharging from the culvert is no longer contained within the channel. This is due to the culvert's invert level being lower than the level of the stream lining at the discharge point, causing water to flow beneath the lined channel. As a result, sediment has accumulated near the culvert outlet.

The proposed works involve modifying the existing stone-lined culvert to intercept and convey flow to a suitable downstream location. At this point, a V-notch weir will be installed to discharge into the lined stream, allowing for accurate flow measurement.

Due to the risk of sediment build-up within the culvert, a CCTV survey will be required to assess sediment volume. If necessary, sediment will be removed to prevent future obstruction of the monitoring structure.

The estimated budget for the works is £80,000.