Holderness Drain - Castlehill Aquagreen (Flood Storage) consultation

Overview

The Castlehill Aquagreen, is part of the £28 million Holderness Drain Flood Alleviation Scheme (FAS) which aims to reduce flood risk for homes and businesses in the Holderness Drain catchment.

This is a partnership project, led by the Environment Agency and supported by Hull City Council, East Riding of Yorkshire Council, Highways England and the Humber Local Enterprise Partnership’s Local Growth Fund Programme.

Please note that our proposals for the aquagreen are completely separate to the proposals you may have already seen or heard about for housing on land to the south of this site at East Carr. If you have any questions relating to this, please contact Hull City Council.

Update for January 2021

The latest newsletter for the proposed Castlehill Aquagreen is posted below, providing a summary of how we have used the results from the public consultation held last year to adapt our designs for the scheme.

Update on the consultation, December 2020

We have now published our findings from the consultation, both as a summary and the full report.  You can access them here:

They can also be downloaded from the list of documents at the bottom of this page. These reports set out the main points raised from the consultation and how we have responded to them.

Current activity on site, December 2020

At the beginning of the month, we carried out work along the Holderness Drain to reduce flood risk and increase protection for areas where water first spills out of the drain during a flood.

The work involved either creating low walls by pushing interlocking plastic sheet piles into the ground alongside the drain or compacting locally excavated soil into low embankments.

We hope to complete the work before Christmas. This will complement the aquagreen (flood storage area) planned for Castlehill and the large pumping station currently under construction down at the docks in East Hull.

Proposals for an Aquagreen at Castlehill

Homes in North Carr and Sutton are at risk of flooding from water held in Holderness Drain after heavy rain. When the Holderness Drain becomes full, water then flows into Sutton Cross Drain, overwhelming the local drainage system and threatening houses nearby.  This came close to happening last November when extremely wet weather caused flooding in other parts of Hull.

Flood water in Holderness Drain, November 2019.  Photo courtesy of Jessica Fox, Hull City Council

To reduce the risk of this happening, land at Castlehill has been bought to create an aquagreen and provide extra space to temporarily store flood water. The site for the aquagreen is shown on the map below, with site boundaries marked in red.

Outline map of the Castlehill site.

The attached plan shows the proposed details for the site.

Creating the aquagreen will involve digging an extra drain, east of the existing Sutton Cross Drain, building a new embankment beside it (shown as number 11 on the plan) and digging a long wide ditch - called a swale (number 9), at the southern end of the site to increase the storage capacity of the area during a flood.  Once the flood is over, water will drain away and, although the site is designed to be ‘wet’ in some areas, flood water will not be held permanently on the site. These features form the aquagreen and will help to control the flood water, keeping it away from homes in North Carr and Sutton.

We will also raise the level of several low spots on both sides of the Holderness Drain to reduce the risk of ‘overtopping’ and flood water spilling out onto the land next to the drain. 

Flooding on farmland next to the drain, winter 2018

Benefits of the scheme

The main benefit of this scheme is to significantly reduce the likelihood of flooding for homes in the North Carr and Sutton areas of Hull, storing flood water in the aquagreen and keeping it away from homes.  Under normal weather conditions, the site will not hold water.

This gives us an opportunity to create a more attractive place that people can enjoy spending time in, offering green space for walking, cycling and appreciating nature.  This could include:

Improving access to the site and creating a network of paths: At present paths on this site are not well connected and become very muddy when it rains.  We would like to make it easier for people to walk, cycle and ride on the site by installing a network of accessible paths and bridleways, as shown on the map.  These new paths could link into current paths, including the Trans-Pennine Trail.  Some paths could be made suitable for wheelchair users and pushchairs, if desired, to make it easier for people to use them.  In addition we would like to install a new path and footbridge to give access to the site from Bransholme (number 10 on the plan).  What sort of pathways do you think would best for your community?  Tell us what you would like to see on this site.

Creating space (habitats) for wildlife: At the moment the site is largely open farmland and not very friendly or welcoming for wildlife.  To improve on this situation, we want to create a range of different habitats to encourage birds and animals on to the site.

We would like to plant a stretch of woodland (number 1 on the plan) on the site between the existing Sutton Cross Drain and the new drain. This will include a mix of native tree and hedgerow species, as shown on the map under ‘planting schedules’.

The plan also includes an area of hay meadow (number 3), patches of scrubland (numbers 2 and 4), some reed beds (number 5), several small ponds (number 7) and some new hedgerows (number 8) in other locations around the site. Together these will provide a variety of important habitats for wildlife in the area.  What habitats would you expect to see in your local area?

Motorbike barriers and places to sit down: we would like to install motor bike barriers on some paths, as well as regular resting places with logs and boulders for sitting on. We would appreciate your views on where might be good locations for these to be placed.

The Castle Hill monument: we would like to offer better protection for the Castle Hill monument (number 6 on the plan) by restricting access so that only people on foot can enter the area around it and installing some information boards about the history of the site, if this was desired.

What happens next

We will review all the feedback we receive and use this to inform the design of the scheme. We will then produce a report explaining how we have used your comments to develop our plans, which we will publish here.