The Wadi Hanifah is a natural watercourse and wetland with flows supplemented by groundwater and discharge from Riyadh. The area, having been undervalued in the past, was subject to a restoration and enhancement programme. The Al Ha’ir Lakes, located to the south of Riyadh, were a significant part of the restoration and enhancement programme. The Lakes cover a combined area of approximately 35ha and are ‘in-line’ with flows from the Wadi Hanifah entering the Lakes at the upstream end, then passing through the lakes and leaving at the downstream end via a second weir.
We were commissioned to advise on ecological issues for the project, including potential ecological enhancement options and likely ecological effects.
What we did
- We conducted a thorough review of documentation for the project, including plans of the Al Ha’ir lakes and previous reports.
- Our experienced team undertook a site visit to gain an in-depth understanding of the Wadi Hanifah system. Observations of the flora and fauna were made, as well as water quality.
- Following the documentation review and site visit, an assessment of the biodiversity potential under various scenarios was made.
- Water quality and depth scenarios were evaluated and we advised on the likely effect of these on lake ecology.
- Current designs and water regimes were assessed in order to ascertain whether biodiversity potential could be achieved or not.
We suggested various methods for enhancing the biodiversity value of the lakes. Shallower water, vegetated banks and the formation of reedbeds and scrub were found to produce higher biodiversity potential. Seasonal pools and wadis were also found to provide enhanced biodiversity potential, as this is the natural habitat of the area. The utilisation of sediment traps, an effective monitoring system and water diversion capabilities were also suggested to maintain higher water quality.