Following several rounds of engagement with Central Bedfordshire Council lasting over a year, Biggleswade Town Council recently conducted a series of tests to try to determine the cause of the flooding issues at the Rose Lane Car Park.
The photographs below show the procedure of the tests carried out.
A green dye was added to the Highways manhole and Highways gully pot. The green dye in the Biggleswade Town Council manhole clearly showed that the dye in the system came from the adjacent Highways manholes and gully pots. The map below shows the Highways drainage system.
The tests prove that the Highways drainage system is clearly connected to the system within the car park and is causing over capacity. The dye testing and rodding of the outlets and inlets are a clear indication of the result.
The video below shows that the system is backed up and over capacity as it is filling up as quickly as it is being sucked out. The water coming in is from the Highways manhole; this has been established using rods and the dye test.
The overcapacity of water displaced into the passive soakaway of the car park, designed and installed in 2015, is directly causing the flooding of the car park, as there is no outlet for the capacity of water generated by the connections from the Highways system.
In order to remedy this, drainage engineers will need to establish an outlet for both systems. If this is not remedied soon, the flooding issues will persist for the foreseeable future. CBC engineers have agreed to formulate an action plan to resolve the root cause of car park under capacity. This will take time to achieve and the Town Council will keep residents and businesses updated.
It should be noted that Biggleswade Town Council leases the car park from a freeholder. The Town Council in its capacity as car park tenant, routinely strives to provide a good car park environment although resolution of the flooding issue is slowed further down by the Town Council not having full legal control of the car park.
