Habitat creation, Langford Quarry
A hydrological and hydrogeological assessment of the proposed restoration of the site to reedbeds and lakes designed to attract wetland bird species.
The design was developed in close collaboration with the RSPB to ensure that the habitat was particularly suitable for Bitterns (a Biodiversity Action Plan (BAP) priority species). A system of weirs was proposed that would control water level and discharge for each of the reedbed areas and a water balance model was created to assess the influence of rainfall, evapotranspiration, groundwater and stage levels in the River Trent.
Using this model the feasibility of the quarry restoration was assessed and optimisation of water management and the weir levels undertaken.
By the time the site is fully restored in 2025 it is envisaged that 63 hectares of reedbed will have been created. When complete, not only will Langford Lowfields be capable of supporting breeding bitterns but will also act as a migration corridor.
Cannon Hall Park, Barnsley
Assessment of 3 historic interconnected lakes and 2 independent waterbodies, located in a large public park. The waterbodies were suffering from significant siltation and low biodiversity.
A water balance was undertaken to identify the water sources and assess water loss through leakages. Water quality was analysed within each waterbody and in the watercourses upstream of the lakes to identify sources of poor water quality.
Recommendations were made to create a silt trap at the point where the watercourse entered the lakes. Other suggestions were made to improve the lakes water quality, such as a "soft engineering" option to limit further degradation of the lake bank and methods to reduce pollution from surface water run-off.
Walpole Park, Ealing - development of park
Assessment of historic waterbodies at the site to determine potential rehabilitation measures. Water quality was assessed together with the relationship of the ponds to the surrounding water environment. The original water source for the ponds had been replaced by a mains supply and the lakes lined with cement. Alternative water supplies for the park were investigated.
Astley Ponds, Chorley
A number of ponds in urban public spaces were selected for improvement to maximise the ecological value of the sites. Hafren Water worked closely with ecologists to determine the water supply mechanisms and the quality and quantity from each source. High nutrient levels were a significant factor in promoting algal growth and isolation of the nutrient source was key to designing a remediation strategy. The study concluded that the ponds received a significant groundwater input from sand horizons within the superficial deposits. The quality of the groundwater was considered to be good and not the source of the nutrient loading (eg leaking sewer).
Prees Heath, Shropshire. Design of a new wetland.
A new wetland area, informed by the local habitat, was designed utilising locally available resources. The design included:
- An open watercourse to replace a culverted section of the existing field drainage system
- Maximisation of wetted perimeter using foot drains
- Creation of several small waterbodies fed by either surface water or groundwater
- Excavation and landforming to intercept the watertable and create a seepage fen
- Increase of the extent of existing reedbeds in a poorly-drained area, with additional water level control
- Proposal for water level control structures and outlet weir to increase water levels and water retention on-site and allow seasonal flooding for willow control
Aerial photograph
Groundwater hydrograph
Lindow Moss, Cheshire. Re-wetting of moss
Hafren Water was appointed to inform the design and undertake an impact assessment for the restoration of a peat works. The proposals primarily included the re-wetting of a large area of peat bog.
Assessment was undertaken to determine groundwater levels within the area and the influence of dewatering by the existing peat works. This included monitoring of surface and groundwaters and determination of peat and underlying sand permeabilities. Work was undertaken in close consultation with consultant ecologists, Natural England and the Environment Agency to determine the feasibility of controlling water levels to enable peat generation to be re-established.
It was found that careful water management would be required to achieve the proposed restoration for ecological benefit as the principal water-supported features being fen and bog, would require different hydrological conditions. The former are groundwater-supported and would be created in the low-lying sections of the site, whereas the bog would be created in peat worked at higher elevations where direct contribution from groundwater would be precluded.
Naturally restored former peat workings
Current peat workings
MIRO-funded project: water-based quarry restoration
A 3-year research project was undertaken on "Water-Based Quarry Restoration" with funding from the Minerals Industry Research Organisation (MIRO). Numerous water-based restoration options were examined incorporating fens and mire, reed beds, wet grassland and the potential for floating wetlands. Habitat creation was also studied alongside other potential end uses for sub-watertable quarry workings including amenity and renewable energy options.
A summary of the aims and the final output of the work is given on the project website www.quarry-restoration.com
The impact of contaminated (urban) groundwater on surface water quality
Staff members have detailed knowledge of investigating the impact of contaminated groundwater on surface water quality. From previous research interests (Paul Ellis) the following publications are relevant:
- Ellis Paul A, Rivett Michael O (Journal of Hydrology, 2010 subject to revision). Urban baseflow influence upon inorganic river-water quality: the City of Birmingham aquifer - River Tame headwaters catchment, UK
- Ellis P (2008). Modelling urban river-aquifer interactions: an industry perspective. Abstract submitted for NERC Hyporheic Network & Groundwater Modellers Forum, 13th March 2008
- Rivett MO, Ellis PA, Greswell RB, Ward RS, Roche RS, Cleverly M, Walker C, Conran D, Fitzgerald P, Willcox T, Dowle J (2008). Cost-effective mini drive-point piezometers and multilevel samplers for monitoring the hyporheic zone. Quarterly Journal of Engineering Geology and Hydrogeology; Volume 41, Issue 1, pp 49-60
- Ellis Paul A, Mackay Rae, Rivett Michael O (2007). Quantifying urban river-aquifer fluid exchange processes: a multi-scale problem. Journal of Contaminant Hydrology, Vol 91, (2007), pp 58-80
- Ellis PA, Rivett MO (2007). Assessing the impact of VOC-contaminated groundwater on surface-water quality at the city scale. Journal of Contaminated Hydrology, Volume 91, 2007, pp 107-127
- Rivett MO, Roche RS, Fitzgerald PJ, Willcox T, Ellis PA, McLanachan P (2006). Evaluation of VOC fluxes from urban groundwater to surface water at various reach scales. Geophysical Research Abstracts, Volume 8, 09146, 2006, SRef-ID: 1607-7962/gra/EGU06-A-09146
- Shepherd KA, Ellis PA, Rivett MO (2006). Integrated understanding of urban land, groundwater, baseflow and surface-water quality - The City of Birmingham, UK. The Science of the Total Environment, Volume 360, pp 180-195.
- Ellis Paul A, Rivett Michael O, Mackay Rae (2005). Assessing the impacts of a groundwater pollutant plume on the River Tame, West Midlands. Abstract in: Proceedings of Geological Society (Hydrogeological Group), Groundwater - surface water interactions in the hyporheic zone meeting, London, 9th May 2005
- Ellis PA, Rivett MO (2004). VOC-contaminant fluxes from groundwater to surface water at the conurbation-scale. Abstract in: Proceedings of Groundwater Quality 2004, 4th International Conference, 19-22 July 2004, University of Waterloo, Waterloo, Canada
- Ellis PA, Rivett MO, Mackay R (2004). Estimation of groundwater-contaminant fluxes to urban rivers. In: Hydrology: Science & Practice for the 21st Century, British Hydrological Society (Publ.) 272-279. [British Hydrological Society's International Conference, London, July 2004
- Ellis PA, Rivett MO, Mackay R (2004.) The Groundwater Contribution to Urban River Quality - River Tame, West Midlands. In: Proceedings of "Water on our doorsteps: Hydrology of urban areas in the UK". BHS (British Hydrological Society) National Meeting, 12th May 2004, Wallingford, UK, pp 1-4
- Ellis PA (2003). The impact of urban groundwater upon surface water quality: Birmingham - River Tame study, UK. PhD thesis, School of Geography, Earth & Environmental Sciences, University of Birmingham, UK, pp 360
- Ellis PA, Rivett MO, Henstock J, Dowle J, Mackay R, Ward R, Harris R (2002). Impacts of contaminated groundwater on urban river quality - Birmingham, UK. In: Groundwater quality: Natural and enhanced restoration of groundwater pollution (Proceedings of the Groundwater Quality 2001 Conference, Sheffield, UK, June 2001), IAHS publication No 275, 71-77
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