Grass cover: improving establishment & resilience to deal with increasing stresses

Overview

Maintaining healthy grass cover is necessary for safeguarding the resilience of embankment dams and levees and is critical if they are designed to overflow.

Grass will tolerate a range of operational stresses ranging from drought to saturated ground if:

• The type of grass is appropriately selected and is sufficiently diverse;
• Care is given to proper establishment; and
• Sufficient attention is given to maintenance all year round.

The use of standard ‘grass only’ mixes, is likely to lead to disappointment if it is unsuited to the local site conditions and not measured against a sufficiently robust specification.

The presentation will draw on the contents of a paper, jointly written by Mike Hughes (Atkins) and David Holland (Salix River & Wetland Services Limited), published in the Proceedings of the 21^st Biennial Conference of the British Dam Society held at Nottingham University from 15 to 17 September 2022.

The presentation will provide a practitioner’s viewpoint on the importance of grass cover and explore a number of current industry publications and specifications to provide recommendations for more easily enforceable definitions of what acceptable grass cover is. The presentation will also question the standardised approach of specifying grass only seed mixes, and whether more diverse seed mixes including a small percentage of appropriately selected herbs or legumes may instead be beneficial and whether resilience can be improved by selection based on observations of existing grass diversity in the embankment and adjacent areas.