The St. Mary's Loch (SML) Option (Cell No. 7)

The St. Mary’s Loch (SML) Option is one part of the Selkirk Flood Protection Scheme’s (FPS) Preferred Scheme. It offers an innovative and sustainable approach to reducing flood risk to the Yarrow Catchment.

These benefits include: reducing the flood risk to the Yarrow Catchment in the Yarrow Valley; and from the Ettrick Water between the meeting of the Yarrow Water and Ettrick Water to the confluence of the Ettrick Water with the River Tweed. Of specific note such measures will increase the level of flood protection to the communities at Yarrowfeus, Yarrowford, Selkirk and Lindean.

The SML Option involves making better use of the existing Control Structures located at the Outlet of SML, to utilize the ability of the Loch to store more flood water and thereby reduce downstream flood risk. Please click on the images provided to see the existing Outlet Structure:

At this point however the SML Option is only a concept and the text approved by the Council Executive in the Report on the Preferred Scheme for Selkirk is:

“To continue work to establish a new management system at St. Mary’s Loch which will deliver a level of flood risk reduction to Selkirk (including Lindean) and the Yarrow Valley.”

The Project Team is currently continuing this work through the development of a Feasibility Study. This study is looking at the possibilities for applying a new management system to the Loch, including possible modifications to the existing SML Outlet Structure. Associated with this Study the Project Team have been undertaking Topographic Surveys around the perimeter of SML so that the effects of changes to the Loch's Water level can be understood.

This Feasibility Study, and all other aspects of the SML Option, will be reviewed by the SMLWG. For more information on the SMLWG please click here.

In the event that an agreed solution can be achieved by the SMLWG it will be fed back into the Selkirk FPS for formal approval within the Scheme under the appropriate Flood Legislation.

St. Mary's Loch in Context

SML is a large (approx. 57M (i.e. 57,000,000) m3 of water) and deep (up to 47m deep) natural fresh water Loch

The outlet has been altered by human design for centuries – e.g. by the Mill Owners in Selkirk

The Megget Scheme was conceived in 1960s, developed in 1970s & completed in 1983 for Raw Water Supply

A Control Structure and Fish Pass was constructed at the outlet of SML as part of the Megget Scheme

Scottish Water (SW) currently manage the (SEPA) CAR License which regulates the Outlet of SML

The SML Catchment is a sub-catchment of the Yarrow Catchment which in turn is a sub-catchment of the Ettrick Catchment

The water draining out of the SML Catchment can be controlled at the existing outlet at the downstream end of SML

The SML Outlet currently provides semi-natural attenuation in its current state

“The Selkirk FPS Project Team will review the way the Loch is currently managed (through the existing CAR License) and consider all viable flood protection options and all user requirements in reporting to the SMLWG. ”