COMHAIRLE CONTAE ÁTHA CLIATH THEAS
SOUTH DUBLIN COUNTY COUNCIL
MEETING OF ENVIRONMENT, PUBLIC REALM AND CLIMATE CHANGE SPC
Tuesday, February 16, 2021
HEADED ITEM NO.
HEADED ITEM: M. McAdam
Flood Alleviation and Surface Water Schemes
REPLY:
River Poddle Flood Alleviation Scheme
The scheme is still currently in Part 10 planning with An Bord Pleanala (ABP).
Following the extension of the statutory consultation period on three occasions by ABP from April 16th 2020 to June 14th 2020 due to national Covid-19 restrictions that were introduced, a Request for Further Information (RFI) was received from ABP on July 27th, on which a response was issued to ABP on October 17th.
The RFI contained 18 items that were responded to, mainly containing further information on biodiversity enhancements, specific tree replacement and species types proposals along with providing supporting documentation on details of public consultations and engagements, noise levels, surface water network management and the locating of site compounds and storage areas.
Following the review by ABP of the information contained in the RFI response, the information was judged by ABP to be of Significant Further Information (SFI) and a further consultation period was instructed by ABP. This consultation took place from November 20th 2020 to January 7th 2021 and was focused on the implications of the proposed development, if carried out for proper planning and sustainable development in the area or areas concerned, the likely effects on the environment and the likely significant effects of the proposed development on a European site.
Following the SFI consultation, 10 further submissions were received and a follow up response to the submissions was provided to ABP on February 5th 2021
The ABP target date for a decision on the scheme is now currently March 26th 2021.
In May 2020, approval was granted by the OPW to proceed to detailed design stage and detailed design works have now been completed on the main elements of the proposed scheme such as flood defence embankments, structural flood defence walls, the flow control structure in Tymon Park and trash screens for vulnerable locations. In relation to the proposed main embankment in Tymon Park and following an extensive review, the requirement for a sheet piling foundation for the embankment has been completely removed, thus further reducing the impact on the park.
Alongside the main elements, detailed Designs have also been completed on the Integrated Constructed Wetland in Tymon Park along with the design for the proposed river realignment in Whitehall using natural river restoration methods. These designs were carried out in conjunction with the Dublin Urban River Life project and SDCC Public Realm.
Initial landscaping layouts for the scheme, in conjunction with SDCC Public Realm and DCC Parks Department have also been developed along with a Feasibility Study on the introduction of natural bank stabilisation methods for the Wainsfort area.
Subject to a favourable decision from An Bord Pleanála in Q1 2021, construction is hoped to commence in Q3 2021.
Full details on the scheme can be found at www.poddlefas.ie
Camac Flood Alleviation Scheme
Stage 1 – Preliminary Design commenced in November 2019 with an estimated completion date of Q1 2022. Delays in Stage 1 have been encountered due to Covid-19 restrictions.
Data collection has been completed and in 2020 the required environmental seasonal reporting and surveys on birds, flora and fauna, bats, mammals, and aquatic life were also completed, with a Wintering Birds Survey to be completed in Q1 2021.
A hydromorphical assessment desktop study in conjunction with the UK River Restoration Centre has also been carried out on the catchment. This is an assessment which considers the physical character and water content of the river along with evaluating the aquatic habitat composition and the dynamic nature of water bodies to achieve sustainable river restoration methods.
In Q3-Q4 2020 a topographical level survey along the river environs was carried out in conjunction with a Bathymetric (Bed Level) Survey of the Brittas Lakes, the Corkagh Park ponds and the Ballymount pond. CCTV surveys of culverts associated with the river network are currently being compiled and are expected to be finalised by the end of Q1.
The hydrological analysis of the catchment commenced in Q4 2020 and in Q2 2021 works will begin on the hydraulic modelling of the river. Following the completion of the hydraulic modelling works, defence optioneering is expected to commence in Q3 2021.
Efforts are also currently being made to host some form of further public information event in Q2 2021.
Progress on the scheme can be found at www.camacfas.ie
SURFACE WATER MINOR WORKS PROGRAMME 2021
- Minor Surface Water Capital Works 2021:
|
Location |
Project Details |
Projected Exp. For 2021 |
|
Templeogue Village Main Street |
Initial assessment and feasibility for new surface water sewer – slit trenches to determine location of underground services |
€220,000 |
|
Palmerstown Woods |
New surface water pipeline required to provide improved connection to surface water network |
€210,000 |
|
Rathfarnham Lake supply upgrade |
Relaying of part of surface water supply pipeline in private property and installation of alarm. |
€5,000 |
|
Projects carried over from 2020 |
Project to upgrade surface water in Sylvan Close, Kilnamanagh, pipework completed in January 2021 and reinstatement in progress |
|
|
Total |
|
€435,000 |
The majority of the above schemes are at design stage and are subject to detailed design and full budgetary estimates.
- Flood Alleviation Minor Capital Works – River & Stream 2021
|
Location |
Project Details |
Projected Exp. For 2021 |
|
Camac River |
Clearing of fallen trees and overgrowth |
€20,000 |
|
Dodder River |
Clearing of fallen trees and overgrowth |
€25,000 |
|
Poddle River |
Clearing of vegetation |
€30,000 |
|
Jobstown Stream Tributary |
Upsize/replace pipework from N81/DeSelby to discharge to 525mm to remove botteneck. |
€45,000 |
|
Mill ponds and Camac screen |
Replace river screens |
€15,000 |
|
Owendoher Stream |
Clearing of fallen trees and overgrowth per tree survey 2020 |
€25,000 |
|
Oldcourt Stream |
Outfall bank stabilisation works |
€30,000 |
|
Ballycragh Lake |
Clear out debris and silt from lake |
€60,000 |
|
Total |
|
€250,000 |