Application ref number – 2014/62/91282/E – Land off Woodward Court/ Hepworth Lane, Mirfield – Bellway Homes
On the south west adjacent to Hepworth close lies the quarry hole worked many years ago. This area was probably worked to provide the stone to build Balderstone hall.
Objection, Sustainable Urban Drainage Systems (SUDS” = (Soak-away)
On Hepworth Close there are 8 number properties with low back gardens, of which 4 properties stand 2m below the finish ground level of the site. These 8 properties have finish floor levels that are between 0.400 – 2.200 below the existing site level.
The dry stone boundary walls, of which the foundations are directly built on top of the rock seam.
The rock head is stated to be 2m below the existing ground level throughout the field. The field falls NE to SW, and NW to SE. Hepworth close is sited on the falls NE to SW, and NW to SE boundary of the site which is down stream of the proposed development.
Hepworth Lane, Hepworth Drive, are both sited on the SE, and SW boundary of the site with several properties below the existing ground level of the site. Some of these have a finish floor levels between 0.500mm – 0.700mm below, which are down steam of the proposed development.
If SUDS were to be used within this areas of the development boundaries, and not excluding beyond the boundary areas the SUDS discharge of surface water runoff would follow the top of the rock head effecting properties adjacent to the proposed development.
In the event of rain-fall over a period of days followed with, cloud busts, and or extreme weather conditions, SUDS would be overwhelmed creating below ground flooding, and the possibility of over ground flooding to adjacent Properties.
The use of SUDS on high ground, and with excessive ground cross falls, and boundary properties downstream. “SUDS is a serious design error for this development”…
As a property owner that falls within the area of this objection I request clarity, and information directly from Kirklees Metropolitan Council (Planning Department) regarding this objection, and a guarantee that if this development is approved, and developed, that my property will not be at risk from flooding with the installation of SUDS…
Explanation, photos of Sustainable Urban Drainage System (SUDS)
S.U.D.S is basically a new set of words for Soak-Away’s all you do is excavate a hole cover the base, and sides of the excavation with geotec material, place plastic aqua-cells modular units in the envelope formed by the geotec material, then rap over the aqua-cells to form a seal.
The photos illustrates one in let 100mm pipe, and one 100mm inspection pipe once work is complete you fill around, and on top of the aqua-cells with clean 10mm gravel then back fill with sub-soil, and top soil to finish ground level.
S.U.D.S is expected to mimic natural conditions. Sustainable drainage systems cover the whole range of sustainable approaches to surface drainage management. They are designed to control surface water runoff close to where it falls and mimic natural drainage as closely as possible.
This is what S.U.D.S needs to mimic:
It is impossible to mimic the natural runoff of a site: when you remove 60% of the grass, and 60% roots which absorb the rain to feed the grass.
Top soil acts as a natural attenuation system when you remove 60% top soil from a site you remove attenuation.
With the time it takes rain to filter though the grass, and roots, top soil, because this is a slow process we will also see water evaporation before it reaches sub-soil level.
In essence 40-50% of rain is removed before the water reaches the sub-soil? This is based on removing 60% field and replacing it with hard standings.
The problems with S.U.D.S are as follows:
S.U.D.S cannot be used on high ground, and not on a boundary of low lying existing properties, not in none permeable ground.
Please remember, how can, S.U.D.S control, manage surface water runoff when you cannot turn the rain off.