How can the catchment upstream of Uckfield be managed to help reduce
flood risk?
Here are a number of suggestions:
1. Shallow gradient floodplain lands could be identified where low level
embankments coupled with outlet controls could achieve flood storage.
Example areas identified were Buxted Park, Coes Rough, and Howbourne
Farm.
2. The use of smaller embankments reduces the cost and regulation involved
in reservoir construction and could be simple structures such as earth or
dense vegetative hedgerows and track ways with good construction.
Where possible the use of existing features could be exploited.
3. Steep or narrow sections of the catchment could be roughened in flood
conveyance terms to increase attenuation within the floodplain i.e. dense
vegetation could be planted.
4. The river Uck and its tributaries upstream of Uckfield have suffered severe
bed erosion in recent (30-50 years) times. This is likely to have resulted
from historic straightening and dredging practices plus land use changes
in the catchment. This seems to have encouraged greater flows within the
channel resulting in greater erosive velocities on the riverbed, an effect
that can increase with time. The resulting deeper wider channel floods less
frequently and the floodplain is under utilised during flood events in the
upper catchment. With these conditions, runoff from the upstream
catchment is efficiently drained potentially increasing peaks in Uckfield.
This trend could be reversed using techniques that encourage better use
of the floodplain whilst also enhancing the environmental value of the river
system and reducing future erosion problems and expenditure.
5. Changes in land use practice outside the floodplain and in the steeper
floodplain areas could increase interception and infiltration with the
associated runoff reduction. Although the runoff fraction in the Uck
catchment is likely to be naturally high during intense rainfall events there
are widespread environmental benefits to managing land to better store
water and promote infiltration. The use of Agri-environment and Woodland
scheme grants could be investigated to help fund the change of land use
practice to encourage landowner participation.