Flood and Water Management Act 2010 GORDON HUNT COUNTY DRAINAGE ENGINEER OXFORDSHIRE COUNTY COUNCIL

Transcription

1 Flood and Water Management Act 2010 GORDON HUNT COUNTY DRAINAGE ENGINEER OXFORDSHIRE COUNTY COUNCIL

2 From : APRIL 2011 Oxfordshire County Council is the THE LEAD FLOOD AUTHORITY and the SUDS ADOPTION BODY (SAB) and has a DUTY To PROMOTE and ADOPT SUDS

3 Requirements:- Promote SUDS on all Developments Check and approve the Design of the SUDS Check their Construction If 2 Properties connect to one SUDs feature the SAB is required to adopt Adopt and Maintain Suds to the required Standards

4 I Believe:- The County Council should lead by Example On all its own Developments Therefore any County Council Development will have a SUDs element. I have found generally we can get some type of SUDs in. But you have to be prepared for the odd exception. As with any development you have to be realistic.

5 The Procedure:- At Pre-Apt or full Application to the Planning Authority The Drainage Element will come to the County Council (SAB) for approval. a The SAB will consult with the EA and other relevant bodies as required. The SAB will approve or consult with the Developer over the application. Within the Planning Application Time the SAB will reply to the Planning P Authority. The Developer can not commence work on site until he has SAB approvad the Drainage Design. The Developer has the right of Appeal.

6 Personnel to cover new responsibilities (plus existing duties and Drainage Program) County Drainage Engineer 4 Senior Engineers 2 Flood students (1 first year + 1 second year) 1 Apprentice Admin support Is this enough?????

7 Other Duties:- Maintain a Public Register of all adopted SUDS. Maintain a Public Register of all Flood Structures. Take over the responsibility of consenting the piping of Non Main River Watercourses (Ditches). Investigate all flooding within its boundaries by working with the other Authorities. Plus - Sort out Legal Agreements

8 Design and Maintenance of SUDS to New National Standards To be Issued in 2011 hopefully. Types of SUDS that can be used:- SWALES GRASS CUTTING & Litter Picking. SOAKAWAYS (tests required) AS REQUIRED. PONDS & REED BEDS (Wet or Dry) AS REQUIRED. FILTER DRAINS JETTING AND TOP P SURFACE REPLACEMENT. CONNECTION OF PROPERTY SUDs KERBLINE DRAINAGE BY CHAMBER AND EASEMENT ON SYSTEM. JETTING ONCE EVERY 2 YEARS. BY CONNECTING ROOF WATER IN THE BACK OF THE KERB THIS CAN DECREASE. POROUS PAVEMENT (tests required) SUCTION SWEEPING TWICE A YEAR, WEED KILLING ONCE EVERY TWO YEARS (SPRING). NOTE SUCTION SWEEPER AT AN ANGLE NOT HORIZONTAL TO SURFACE.

9 COSTS:- AFTER APRIL 2011 THE SAB in Oxfordshire will:- The SAB:- will actively check the DESIGN and the CONSTRUCTION of all SUDs features. This will be done initially by working closely with the Consultants nts where possible to save them time and money, but mainly to get them on board on how we work in Oxfordshire. Charging for checking the design and construction, we now know will w not come in until late 2011 or early 2012 But in Oxfordshire we intend to actively carry on and promote SUDs and offer to adopt. A Charge will be made for future maintenance of the SUDs feature as we have done in the past.

10 Working with Consultants can produce good SUDs schemes

11 Sheet 2

12 DESIGN CRITERIA SOAKAWAY SOAKAGE TEST 2X2X2m FILL BOTTOM 1m WITH WATER AND TIME CHECK SOIL TYPE SILTY SANDY ETC DECIDE HOW MANY TIMES REPLACEMENT REQUIRED IN 25 YEAR PERIOD ADD FOR SMALL SETUP AND REPLACEMENT OF PLANTING

13 POROUS PAVEMENT SOAKAGE TEST 2X1X 0.5m SOME SITES MAY NEED DEEPER TRENCHES ACROSS ROAD TO SOAK CHECK DAMS MAY BE REQUIRED TO SLOW FLOW DOWN OVERFLOW PIPE - 3m FILTER DRAININTO STONE OVERFLOW INTO EXISTING SYSTEM OR GULLEY

14 POROUS PAVEMENT - DESIGN TWO LAYERS OF GEOTEXTILE REQUIRED - ONE UNDER THE BEDDING STONE THE SECOND ON THE SUB GRADE IF A RUNNING LAYER IS USED DURING THE CONSTRUCTION PHASE THE BEST OPYION IS TO HAVE IT REMOVED AND REPLACED WITH STONE. OR THE LAYER IS CORED (100mm dia.) ON 750mm GRID THE HOLES THEN FILLED WITH STONE. A IMPERMABLE BARRIER IS USED BETWEEN EXISTING ROAD CONSTRUCTION AND POROUS PAVEMENT. A IMPERMABLE BARRIER SHOULD ALSO BE USED WHEN THE POROUS PAVEMENT IS LOCATED CLOSE TO BUILDINGS. OVERFLOWS SHOULD BE INCORPORATED WHERE POSSIBLE. AND IN LINE WITH PPS25 AN OVERLAND FLOOD ROUTE IS PROVIDED.

15 FLOOD INVESTIGATION PROCEDURE

16 FLOOD INVESTIGATION PROCEDURE

17 FLOOD INVESTIGATION PROCEDURE for PARTNER AUTHORITIES Surface Water Flood and Ground Water Preliminary Investigation Time and Date of Flood.. Location of Flood Extent of Flood Flood caused by:- Watercourse. Land run off. Groundwater No of Properties affected.. Flooding of:- Domestic Property. Business Property.. Gardens.. Land Depth of Flooding mm Has this happened before If so how many times.. Please supply sketch plan

18 Designation / Register of Assets Existing Drainage Assets Flood Structures (register provided by DEFRA) We are preparing a GIS web based program to cover this

19 Types of Swales and outfalls

20 Check Dams in Swales

21 Discharges and Swales

22 Types of Ponds

23 Porous Pavement Sites

24 Bad Practice

25 Bad Practice

26 Effective Sites