The Land Water Drainage or Seepage down the Hollins Cross Farm Site in the fields below Crown Point where the proposed development is planned will be interrupted by foundations of any new properties built.
We asked the Council if they had done a land drainage survey, this is to study the Natural Water Drainage of the hillside, under the "The Land Drainage Act 1991" (this underpins the ordinary watercourse regulations that should be undertaken by Local Authorities).
We asked the Council if they had done a survey of the land to decide the necessary type of foundation that the buildings will need and the impact of pollution into streams underground and over ground.
There is a very good Government produced document available that gives guidlines in Preventing Pollution to watercourses. View PDF
This publication is marked as been withdrawn but it is a good guidline.
WaterCourses / Streams are marked in Blue
WaterCourses / Streams at Hollins Cross Farm
The Water Courses / Streams provide an important water collection and drainage mechanism for the field and surrounding hillsides, water flow is slowed down.
Building houses on the hillside will disrupt the natural flows of the streams on the hillside, these streams feed the river that then flows through the culvert below Woodplumpton Farm and under New Road (A646) and down into what used to be the Rock Lane reservoir.
This Culvert which is a fixed diameter at present is on the Flood Risk Asset Register - We asked the Council if they had read this paper.
A recent calculation from a local resident on Wilkie Avenue who is a Civil Engineer shows -
"The rain fall that fell on Burnley on Boxing Day last Christmas, the met office states we had 178 millimeters of rain that day.
An area the size of Hollins Cross Farm some 180,000 sq metres had 3.204 million liters of water fall on it. That's 32,040 tons of water!!
Its simple math's and hydrology.
Most of this water is being trapped by soaking into the site. If this water is allowed to become free flowing from the hillside, drainage systems will be overwhelmed and Burnley Center will be flooded the same as happens to Padiham now. The substation next to Tesco will be put out of action Shops, Offices and the Police Station all without power and it will cost £0000's to repair.
The Hollins Cross Farm site works as a natural free flood defense as it stands today.
I've forwarded to both the council, local plan and MP the same info.
It's simply not safe to build on the site sending thousands of tons of extra water towards the town."
There are water courses / streams running down and across the hill from Crown Point show in Blue in the figure above, these water courses are also augmented with water flowing from natural springs that are present in the hillside, "after all" Farms were always built in the "old days" where there was a source of fresh drinking water - a spring - this was to supply the farmer his family and their cattle.
No building work should be carried out on the Hollins Cross Farm site as this will Damage the ecology of the field - and any re-routing of this natural drainage will result in existing properties on the periphery of the site being impacted.
Nature will always a find a way to reassert its watercourse routes.
A report on the Management and importance of preserving Small Water Bodies can found at this URL View PDF
This publication is marked as been withdrawn but it is a good guidline - for further guidance please consult. The importance of smalwater bodies
Small waters bodies include headwater streams, springs, ditches, flushes, small lakes and ponds. They can be found in all landscapes and by their very nature are highly varied in all aspects, from water chemistry to the species they support. These habitats are vital for freshwater biodiversity but remain largely overlooked and widely excluded from government policies like the Water Framework Directive and River Basin Management Plans which describe how we should be protecting freshwaters.
The Pond at Hollins Cross Farm is very important in the prevention of flooding in Burnley as it traps a large amount of water and allows restricted drainage.
Flushes / Ditches of Hollins Cross Farm are very important in the prevention of flooding in Burnley.
WaterCourses / Streams the land's Capillaries
Installing "Sustainable drainage systems" would also not benefit the Hollins Cross Farm Site as this would create a larger than acceptable volume of water at the base of the site, this larger volume would then be trying to flow into the concreate pipe culvert under the A646.
The result of draining the water off the field faster than allowing the natural seepage into the hillside and forcing it into the culvert would cause what is known as "choked flow", basically the venturi effect. For the layman's view of fluid dynamics this means too much water in one end causes the flow rate to slow down and reduces the efficiency of the culvert. It will backup, overflow and discharge onto the A646.
The only alternative would be a larger diameter culvert, we asked the council if they had done surveys or employed professional bodies to project increased flow rates and costing for the installation of a larger culvert system across a main arterial route such as the A646 into Burnley.