Services
Flood Risk Assessments
Our Flood Risk Assessments (FRA's) are produced in accordance with the requirements of the National Planning Policy Framework (NPPF) and the Environment Agency FRA Guidance. Our FRA's assess the risk from fluvial, pluvial, coastal, groundwater, reservoir and canal flooding on the development/property in question. Our FRA's determine the predicted levels of flooding and suggest property resilience measures in accordance with CIRIA C790.
Surface Water Drainage Design
Our Surface Water Designs assess the predicted volumes of surface water that will be generated for various Annual Exceedance Probability (AEP) events; up to and including the 1% AEP with an additional allowance for climate change. Our designs ensure that area of impermeable surfacing contain sufficient drainage to ensure these areas do not flood. All designs will produce full hydraulic calculations to determine the required pipe sizes, gradients and any attenuation structures, needed for the development, to achieve Greenfield runoff rates. All designs will be undertaken in accordance with the SuDS Manual (CIRIA C753) and include fully annotated general arrangement drawings with invert levels for all pipework and manholes.
Hydraulic Modelling
Our Hydraulic Modelling services include the production of 1D-2D combined models. Our hydraulic models determine the extent, velocity and depth of flood water which then allows our expertise to design appropriate resilience measures. Our modelling services can be used to update existing flood models or can be used to create models for watercourses which are currently outside of any modelled areas.
Surface Water Rainfall Modelling
JCD Drainage Solutions can produce direct rainfall modelling using industry approved 2D modelling software. These 2D rainfall model assess where surface water shall accumulate and to what depth giving you the information required to know the risk to an area. These services could be utilised to determine the flood risk of single dwelling or a large scale commercial or residential development. All rainfall modelling undertaken by JCD Drainage Solutions utilises the latest rainfall data from the FEH Web Service with design hydrographs developed in ReFH2.
Sequential Tests
We can assess and compare your proposed development site, when located in flood zone 2 or 3, with allocated sites within the local plan and other readily available sites; to see if the development could potentially be relocated to a site located within a lower flood zone. Our Sequential Tests will be undertaken in accordance with the requirements stated within the National Planning Policy Framework (NPPF) and the Environment Agency's flood risk and coastal change guidance.
Drainage Strategies
Our Drainage Strategies provide an outline for how surface water should be managed for any proposed development. The reports will calculate the pre-development runoff rate to determine the maximum allowable discharge rate from site; in order to achieve this the required attenuation volumes will also be calculated. The reports will suggest the mechanisms for discharge of surface water, in accordance with the SuDS Discharge Hierarchy, where infiltration is the preferred option when ground conditions allow. Our Drainage Strategies shall be fully compliant with the requirements of the SuDS Manual and will document how water quality, quantity, biodiversity and amenity are achieved by the proposed surface water drainage.