Page 51 - Enfield SuDS DESIGN & EVALUATION
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approach 1                                      approach 2



                           inflow                                           inflow                                 Concept Design


                            rainfall                                         rainfall

                                 x                                               x
                              area                                             area







                  interception losses                              interception losses





                                         other
                  attenuation            long                           attenuation

                     storage             term                              storage
                                        losses

                 variable outflow                                                    outflow for 1in100 yr
                from 1in1 to 1in100yr          2L                                    rainfall event limited
                 greenfield runoff            /sec                                    to 2yr greenfield            46
                     rates                    /ha                                        runoff rate








                    Approach 1 and Approach 2 - Discharge Requirements



                                     1 in 1 year rainfall   1 in 100 year   Long term
                                        (maximum             rainfall        storage-
                                       outflow rate)       (maximum           volume
                                                         outflow rate)        control
                     Approach 1          1 in 1 year      1 in 100 year         Yes

                                      greenfield rate      greenfield
                                                              rate
                     Approach 2        Qbar/ Qmed         Qbar/ Qmed            No







      Enfield Council SuDS D & E Guide                                                                            © 2018 McCloy Consulting & Robert Bray Associates
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