Groundwater v Drains – study needed
I had another opportunity to study the water table – following heavy rain a couple of nights ago, there was an initial flow of water from the North Parade drains. This water immediately sunk through the beach. A couple of days later groundwater is showing past the embryo dune ridge.
I think it’s quite probable that this is another unintended consequence of our ancestors thinking they were doing something useful by draining the carrs behind Hoylake and Meols, but actually they were just saving up problems for the future. Willow is amazingly good at taking groundwater and putting it into the atmosphere by a process called evapotranspiration.
Before WBC spend any money fixing our Victorian drains (a multi-million-pound operation) I’d be quite keen to see if there is:-
(i) any point in doing this
(ii) if it was possible to come up with a more environmentally friendly solution.
I think it’s probably worthy of a whole new FB group because there are so many other possible benefits to reviving the idea of establishing a Wildfowl and Wetlands Centre on the Carrs, which at its most ambitions could be a flood abatement scheme for north Wirral, a water treatment option for Hoylake, Meols and parts of West Kirby. And that’s before we get to Beavers and Otters.
But for now I’ll park it here.
- A visitor attraction [Burton Mere RSPB attracts 40,000 visitors a year, Washington WWT 83,817, Martin Mere WWT 170,000 Leighton Moss RSPB 100,000 etc]
- Sustainable water treatment. Eg 1 hectare of Phragmites reed-bed, removes the need to discharge at sea and offers an alternative discharge point to the drains currently discharging onto Hoylake beach [Masi]
- Reduce flooding in the lower Birket valley through capture, slower release and evapotranspiration of flood and groundwater in the upper Birket [ Marc, Tariq]
- Reduce groundwater discharge onto the beach at Hoylake by lowering the water table [figure 4]
- Carbon Net-Zero target – one reed bed system has been shown to reduce CO2 equivalent by 70 tons a year compared to conventional methods[Edie] . The Carbon sequestration rate of woodland is approximately 70t of CO2 equivalent per hectare per year [Gregg et al 2021]
- Biofuel generation via short rotation coppicing is estimated at 46 MW per hectare per anum a 99.6% in CO2 equivalent reduction per GJ over fossil fuels [Forest Research]
- Biodiversity gain. Wet Woodland, Reedbeds and Coastal and Floodplain Grazing Marsh are all high priority Biodiversity action plan habitats [JNCC]
- A research and education facility
REFERENCES
van Bussel 2006, The potential contribution of a short-rotation willow plantation to mitigate climate change
Edie 2020 Ground-breaking reed bed system cuts carbon for Essex & Suffolk Water
Gregg et al 2021 Carbon storage and sequestration by habitat: a review of the evidence
Harding 2007, The Wirral Carrs and Holms JOURNAL OF THE ENGLISH PLACE-NAME SOCIETY 39 45-57
Hoylake Village Life 2017 Proposals for a Hoylake Eco-Golf Resort Wildfowl and Wetlands Centre
Forest Research– Potential yields of Biofuels per hectare per annum
JNCC 2016 List of Biodiversity Action Plan priority habitiats
Marc, V.; Robinson, M. The long‐term water balance (1972–2004) of upland forestry and grassland at Plynlimon, mid‐Wales. Hydrol. Earth Syst. Sci. 2007, 11, 44–60, doi:10.5194/hess‐11‐44‐2007
Masi et al 2017, Large scale application of French reed beds: Municipal wastewater treatment for a 20,000 inhabitant’s town in Moldova Water Science & Technology 76, 134-146
Tariq et al 2020 Applied Sciences 10(23):8752 A Critical Review of Flood Risk Management and the Selection of Suitable Measures