RHONDDA CYNON TAF COUNTY BOROUGH COUNCIL Flood Risk Management Plan VOLUME 1 Page left intentionally blank Rhondda Cynon Taf C.B.C Flood Risk Management Plan RHONDDA CYNON TAF COUNTY BOROUGH COUNCIL FLOOD RISK MANAGEMENT PLAN VOLUME 1 Rhondda Cynon Taf County Borough Council Headquarters The Pavilions Cambrian Park Clydach Vale Tonypandy CF40 2XX Email: [email protected] i Rhondda Cynon Taf C.B.C Flood Risk Management Plan Page left intentionally blank ii Rhondda Cynon Taf C.B.C Flood Risk Management Plan FOREWORD During recent years, communities in Rhondda Cynon Taf have experienced the severe impacts and consequences of flooding. We have also witnessed other areas of the United Kingdom being subjected to devastating flood events. It is widely held that floods such as these are likely to become more frequent as the effects of climate change develop. The consequences of this unchecked expected increase in flooding will likely see greater risks to life, the economy and the environment of Rhondda Cynon Taf. In response to the above, Rhondda Cynon Taf County Borough Council has developed a holistic response to managing flood risk in the form of its first Flood Risk Management Plan. The Flood Risk Management Plan has been prepared with due deference to the objectives outlined in Rhondda Cynon Taf County Borough Council’s Local Flood Risk Management Strategy, published in 2012. The Flood Risk Management Plan is a key milestone in ensuring that the risk of flooding within Rhondda Cynon Taf is managed as a whole, integrating the work done by the Council, Government Bodies, Water Companies, communities and individuals. The Flood Risk Management Plan sets out the various measures that will be used to both gain a greater understanding of; and manage flood risk within Rhondda Cynon Taf. It should be stressed that the measures outlined within the Flood Risk Management Plan only contribute to the management of flood risk, aiming to assist in the prioritisation of flood risk management interventions where most required. Given the current pressures on public finance, it would be unrealistic to protect all property and infrastructure from the risk of flooding. The Flood Risk Management Plan focuses on local flood risk, defined as flooding caused by surface runoff, groundwater and ordinary watercourses (streams, ditches etc.). This type of flooding was responsible for the highly publicised flooding of 2009, and is as an important mechanism of flooding within Rhondda Cynon Taf as is flooding from main rivers. However, it is appreciated that it is not the source of flooding that is of importance to those affected, but the effects. The Flood Risk Management Plan therefore sets out how Rhondda Cynon Taf County Borough Council will work collaboratively with other key stakeholders to input into the management of all sources of flood risk and ensure that investment decisions are made according to levels of risk. Measures within the Flood Risk Management Plan outline how Rhondda Cynon Taf County Borough Council will attempt to gain a better understanding of the risks of flooding. By using modern modelling software it is possible to determine properties that are at risk from flooding, or are likely to be at risk of flooding in the future. It is appreciated that householders may have concerns about using models to determine areas of flood risk, but they are a significant and important tool in ensuring that limited resources are used in an effective manner to target flood risk measures to areas at the highest risk. The Flood Risk Management Plan presents Rhondda Cynon Taf County Borough Council’s preferred methodology for dealing with and better understanding flood risk and ensuring that communities, infrastructure and the wider environment are more resilient to the impacts of flooding and climate change. Councillor Andrew Morgan Leader of the Council, Rhondda Cynon Taf County Borough Council iii Rhondda Cynon Taf C.B.C Flood Risk Management Plan iv Rhondda Cynon Taf C.B.C Flood Risk Management Plan TABLE OF CONTENTS FOREWORD .................................................................................................................................. iii 1.0 PURPOSE OF THE FLOOD RISK MANAGEMENT PLANS ............................................ 1 1.1 What is a Flood Risk Management Plan? ............................................... 1 1.2 What is Included in this Flood Risk Management Plan? ......................... 1 1.3 Legislative context .................................................................................. 2 2.0 SUMMARY OF RHONDDA CYNON TAF COUNTY BOROUGH COUNCIL .................... 5 2.1 Administrative Area................................................................................. 5 2.2 Land Use ................................................................................................ 6 2.3 Geology .................................................................................................. 7 2.4 Hydrogeology ......................................................................................... 7 2.5 Catchment Characteristics ...................................................................... 8 2.6 Flood Risk in Rhondda Cynon Taf County Borough Council ................ 21 3.0 HOW DO WE CURRENTLY MANAGE FLOOD RISK? .................................................. 24 3.1 Operational Procedures ........................................................................ 24 3.2 Regulatory Powers ............................................................................... 24 3.3 Local Flood Risk Management Strategy ............................................... 25 3.4 Who we work with to manage flood risk ................................................ 31 3.5 Flood Risk Management Functions ..................................................... 33 4.0 WHY DO WE HAVE TO PRODUCE A FLOOD RISK MANAGEMENT PLAN?............. 37 4.1 Preliminary Flood Risk Assessment ..................................................... 37 4.2 Updated Flood Maps for Surface Water ............................................... 40 4.3 How are we drawing conclusions from the uFMfSW? .......................... 41 4.4 What is being counted? ........................................................................ 42 4.5 Flood Investigation Areas ..................................................................... 48 5.0 HOW WE WILL MANAGE FLOOD RISK ........................................................................ 49 5.1 Flood Risk Management Plan Measures for Managing Flood Risk ...... 49 5.2 Strategic Environmental Screening ...................................................... 50 5.3 Flood Risk Management Plan Measures and EU reporting codes ....... 52 6.0 HOW THIS FLOOD RISK MANAGEMENT PLAN HAS BEEN CO-ORDINATED? ...... 57 6.1 Working Groups .................................................................................... 57 6.2 Co-ordination with River Basin District .................................................. 60 6.3 The Severn River Basin District Management Plan .............................. 64 6.4 The Severn River Basin District Flood Risk Management Plan ............ 67 7.0 RHONDDA CYNON TAF COUNTY BOROUGH COUNCIL – BOROUGH WIDE .......... 70 7.1 Overview ............................................................................................... 70 7.2 Conclusions from the uFMfSW ............................................................. 70 8.0 RHONDDA CYNON TAF COUNTY BOROUGH COUNCIL – FLOOD RISK AREA ...... 76 8.1 Overview ............................................................................................... 76 8.2 Conclusions from the uFMfSW ............................................................. 76 9.0 COMMUNITY AREAS ...................................................................................................... 82 9.1 Aberaman North ................................................................................... 82 9.2 Aberaman South ................................................................................... 87 9.3 Abercynon ............................................................................................ 92 9.4 Aberdare East ....................................................................................... 97 9.5 Aberdare West/Llwydcoed .................................................................. 102 9.6 Beddau ............................................................................................... 107 9.7 Brynna ................................................................................................ 112 9.8 Church Village .................................................................................... 117 9.9 Cilfynydd ............................................................................................. 122 v Rhondda Cynon Taf C.B.C Flood Risk Management Plan 9.10 Cwm Clydach ..................................................................................... 127 9.11 Cwmbach ............................................................................................ 132 9.12 Cymmer .............................................................................................. 138 9.13 Ferndale ............................................................................................. 143 9.14 Gilfach Goch ....................................................................................... 148 9.15 Glyncoch ............................................................................................. 153