Hydrological Assessment Report Commissioned by An Bord Pleanàla with respect to PW 3005 / JA0030 Lough Ennell Water Abstraction to Royal Canal Consultant Dr. Pamela Bartley August 2012 Hydro-G 50 Henry St. Galway [email protected] 091 449950 087 8072744 Project No.: 09245_L Ennell_RC Report Status: Final_3 Report Title: An Bord Pleanàla, Westmeath County Council’s proposed abstraction from Lough Ennell to the Royal Canal. Date: 27th August 2012 Prepared by: ___________________________ Dr. Pamela Bartley NOTES: This report is for the use solely of the party to whom it is addressed and no responsibility is accepted to any third party. -ii- Hydro-G Ref 09245_L Ennell_RC An Bord Pleanàla, PW3005 / JA0030: Lough Ennell Hydro-G TABLE OF CONTENTS 1. Introduction -------------------------------------------------------------------------------- 1 2. Methodology -------------------------------------------------------------------------------- 2 2.1. Assessment of Information ------------------------------------------------------------------ 2 2.2. Request for Further Information & Assessment of Response ------------------------------ 2 2.3. Site Visit & Catchment Assessment --------------------------------------------------------- 2 2.4. Hydrological Information of Significance obtained at Oral Hearing------------------------ 3 3. Hydro-G’s Evaluation of the Proposal --------------------------------------------------- 4 4. Addressing Hydrological Concerns Expressed in Written & Oral Submissions -- 14 5. Conclusions ------------------------------------------------------------------------------- 16 References ------------------------------------------------------------------------------------- 17 Appendix A Hydro-G’s Hydrological Calculations------------------------------------- 18 -iii- Hydro-G Ref 09245_L Ennell_RC An Bord Pleanàla, PW3005 / JA0030: Lough Ennell Hydro-G 1. Introduction Westmeath County Council made a proposal to take a supply of raw water from Lough Ennell at Ladestown, Mullingar to supply the Royal Canal. Objections were made to this proposal and were not withdrawn. Westmeath County Council then applied to An Bord Pleanàla for a Provisional Order declaring that their proposal come into force (WCC letter to An Bord Pleanàla dated 7 th December 2011). There are two An Bord Pleanàla references to this case: PW3005 relating to the EIS application and JA0030 relating to the abstraction order. The hydrological issues are the same and are dealt with in an integrated manner in my report. My hydrological report is intended to aid An Bord Pleanàla in their assessment of the proposed Lough Ennell abstraction supply to the Royal Canal in that it provides expert opinion on the water aspects of the proposal. In addition to consideration of the hydrological implications of the abstraction, I have considered the potential of the proposal to affect the hydrogeological regime feeding dependent terrestrial habitats in the vicinity of Lough Ennell and the feeder stream from Lough Owel. For details relating to the proposal, readers are referred to the EIS and NIS accompanying the proposal by Westmeath County Council to abstract water from Lough Ennell, Co. Westmeath to supply the Royal Canal. An Bord Pleanàla has commissioned additional expert advice from an ecologist, Dr. Evelyn Moorkens. This hydrological report is intended to also aid the ecological assessment and readers are referred to Dr. Moorken’s report (August, 2012) for ecological details and independent ecological assessment. The aims of my independent hydrological assessment and report are as follows: a) Evaluate and comment on the justification and rationale for the Abstraction Order; b) To assess the validity of the approach to hydrological assessment undertaken; c) Outline and comment on the potential changes to the hydrology as we now understand it; d) To assess the consequences for water quality, if any; e) To provide a statement regarding the proposal and how it fits with the requirements of the Water Framework Directive; f) Comment on potential impacts in affected watercourses in terms of different hydrological regimes such as low flows and floods; g) Evaluate the proposed regulation of abstractions and flow from Lough Ennell and provide advice regarding the required conditions that should be attached to the sanctioning of the proposal, should that sanction be warranted; h) Evaluate the proposals for the installation/construction phase and pipe design. -1- Hydro-G Ref 09245_L Ennell_RC An Bord Pleanàla, PW3005 / JA0030: Lough Ennell Hydro-G 2. Methodology 2.1. Assessment of Information My initial assessment was informed by the application documentation, including the submitted EIS and Appropriate Assessment Report and submissions received from prescribed bodies and third parties. In addition, I relied upon my civil engineering background and knowledge of hydrology, hydrogeology, eco-hydrology, and groundwater dependent environments. I employed Irish research findings and nationally available datasets for hydrometric and hydrochemical details of significance to the proposal. 2.2. Request for Further Information & Assessment of Response Given the interdependency of the water and ecological aspects of the proposal, I worked in collaboration with Dr. Moorkens in an assessment of the EIS and other case information and we determined that there were deficits in the information supplied, which prevented an integrated hydro-ecological, macro scale, evaluation of the proposal. Therefore, a request for further information was issued by An Bord Pleanàla (March, 2012). Two written responses to the further information (10th April and 30th April) were received by An Bord Pleanàla and these were reviewed by the inspector responsible for this case (Ms. Mairead Kenny), Dr. Moorkens and I. The responses to the further information did not provide the additional information that I needed to complete my assessment of the sureness of the conclusions that could be drawn regarding the simulated hydrological regime that would result from the proposal, potential changes to the lake shore wetting extents and the consequent effects on groundwater dependent terrestrial ecosystems e.g. the designated Alkaline fens. The responses did not provide the details requested to support an independent analysis of hydrological changes in Lough Ennell. Drawings were submitted as requested but not at a suitable scale to facilitate my alternative assessment of impacts and changes of wetting extents of the lake, some items were partially answered with as much detail as the applicant “considered relevant”, items 8, 10, 11, 13, and 16 were not answered and items 5 and 16 both suggested a operation/management strategy that did not comply with the obligations of Statutory Instrument S.I. No. 477 of 2011 (European Communities (Birds and Natural Habitats) Regulations 2011). Further, the conclusions drawn from the hydrological simulation outputs were difficult to rationalise. The oral hearing arranged provided an opportunity to clarify many aspects of the proposal. 2.3. Site Visit & Catchment Assessment Upon receipt of the Further Information and in light of the information deficits, Ms. Mairead Kenny, Dr. Evelyn Moorkens and I visited the site and the catchments of each Lough Ennell & Lough Owel on the 9 th May 2012. During a visual assessment of the catchment, I noted general catchment characteristics, hydrological patterns and anthropogenic pressures. I also recorded -2- Hydro-G Ref 09245_L Ennell_RC An Bord Pleanàla, PW3005 / JA0030: Lough Ennell Hydro-G water characteristic readings at various points on the lake perimeters of Lough Ennell & Lough Owel, streams of interest feeding Lough Ennell & at various points on the feeder canal from Lough Owel. We evaluated the influence of groundwater at various locations. Ms. Mairead Kenny, Dr. Evelyn Moorkens and I visited the site of the Clonsingle weir on the 21 st May 2012. It became obvious during our site visit that the central section wooden gate at Clonsingle was dysfunctional. At the oral hearing it was further determined that the current state of the weir was that control was not possible. In addition, we noted during our site visit that the turbulence downstream of the weir would appear to create a problematic environment for fish passage. We also made observations in the pattern of drainage and the disrepair of control structures on the Monaghanstown stream in the vicinity of Lough Ennell. Information gained in the catchment greatly filled knowledge gaps and provided physical context for information and clarifications that would be sought at the proposed oral hearing. 2.4. Hydrological Information of Significance obtained at Oral Hearing The information gained at the oral hearing clarified all my issues regarding hydrology and the proposed regimes for both the abstraction and discharge from Lough Ennell, and the consequent potential effects. The most significant pieces of hydrological information gained at the oral hearing were as follows: o That there is currently no control of or regulation of water levels in the lake. Water flows from Lough Ennell through the Clonsingle weir with no control of discharge from Lough Ennell to the River Brosna. o The uncontrolled discharge condition is further exasperated by the fact that the River Brosna acts as an enhanced drainage mechanism for Lough Ennell because of the drainage works deepening of the Brosna’s channel carried out by the OPW on the River Brosna in the 1950’s. o As part of the proposal by Westmeath County