It’s not just flow. The importance of groundwater chemistry in superficial quarry applications: a case study Dr Richard Mitchener1, Anna Butler & Dan Jefferies2 Atkins Limited 1 Now at EDF Energy; 2 now at Jacobs UK Introduction • Any project that involves digging holes can affect groundwater – and affecting groundwater can have an effect on ecology, archaeology and even sacred sites • Habitats Directive, Birds Directive, Ramsar treaty and Water Framework Directive have significantly increased scrutiny in recent years • SSSIs getting similar protection/scrutiny? • Recent(ish) court judgements have moved the goalposts? • Natural heritage regulators just as important as the planners and the environmental regulator • Non-statutory stakeholders can help or hinder… • Understanding key issues and concerns early is critical • Gather the right data, at the right resolution 23 July 2019 2 Case Study • Client: Hills Quarry Products Limited • Site: Upwood Park, Oxfordshire • Proposal: Mineral Extraction and Restoration for Low Level Habitat Creation and Inert Filling Site Location • The site comprised four agricultural fields interspersed with mature woodland • Upwood Lies 2km to the north east of Tubney • 1.5 km to the north-west of the village of Cothill Reproduced from a 1:50,000 Landranger Ordnance Survey digital map data © Crown copyright 2004. All rights reserved. Licence number 0100031673. Conservation Sites • Cothill Fen and Parsonage Moor Nature Reserve (SAC & SSSI) • Dry Sandford Pit (geological SSSI) • Hitchcopse Pit Nature Reserve (SSSI) Habitats Regulations • List of Sites proposed by Secretary of State, important for • Habitats (Annex I) • Species (Annex II) • Competent Authority must review planning applications (appropriate assessment) • “…no adverse effect…” • “precautionary principle” • IROPI exception allowed, but highly unlikely to apply minerals sites • Case law reinforces the very high bar 23 July 2019 6 Water Framework Directive • Integrated management of catchments • Need to achieve and maintain “good” status for groundwater and surface water • Complex series of tests applied by Competent Authority (EA) • “groundwater dependent terrestrial ecosystems” given special importance • “WFD Assessment” needed – methodology developing • Similar “get out” as for Habitats directive (Art. 4.7) but again unlikely to apply to minerals projects. 7 What does this mean? • Valley mire ð water is probably important… • Dewatering? • Changes to storage • Changes to drainage and runoff characteristics? • Alkaline fen ð chemistry is probably important… • Changes to water balance • Groundwater/runoff • Remember “…no adverse effect…” 23 July 2019 8 Works Undertaken at Site • Previous ground investigations undertaken in April and May 2006 to establish the extent and quality of the mineral deposit and installation of boreholes. • Installation of groundwater level monitoring equipment in 6 wells Nov 2006 (in (Feb 2007) • Installation of surface water level monitoring equipment in Cothill Fen and Parsonage Moor (April 2007 and June 2007) • Installation of a gauge board in Hitchcopse Pit pond in Feb 2007 • Monthly groundwater and surface water quality monitoring • Permeability testing in a range of boreholes (June 2007) as part of an MSc project • Met station already at nearby site Geology & Hydrogeology A g e S t r a t a Approxim ate Thickness Q u a t e r n a r y Alluvium (clay, silt and sand), peat and D r i f t sands and gravels Upper Jurassic Upper Corallian Sand (Kingston Form ation) 1 0 - 2 0 m Upper Jurassic Lower Corallian Silt (Hazelbury Bryan 0 - 1 5 m F o r m a t i o n ) Upper Jurassic Lower Corallian Clay 0 - 2 2 m Upper Jurassic O xford Clay 9 0 - 1 0 0 m 23 2019 23 July monitoring Groundwater Groundwater Levels (mAOD) Groundwater Level (mAOD) 78.90 78.91 78.92 78.93 78.94 78.95 78.96 78.97 80.75 80.76 80.77 80.78 80.79 80.80 80.81 80.82 01/03/2007 00:00 01/03/2007 00:00 01/03/2007 02:00 01/03/2007 02:00 01/03/2007 04:00 01/03/2007 04:00 01/03/2007 06:00 01/03/2007 06:00 01/03/2007 08:00 01/03/2007 08:00 01/03/2007 10:00 01/03/2007 10:00 01/03/2007 12:00 01/03/2007 12:00 01/03/2007 14:00 01/03/2007 14:00 01/03/2007 16:00 01/03/2007 16:00 01/03/2007 18:00 01/03/2007 18:00 01/03/2007 20:00 01/03/2007 20:00 01/03/2007 22:00 01/03/2007 22:00 BHNR1Data Rainfall and Levels Groundwater 02/03/2007 00:00 02/03/2007 00:00 BH08Rainfall Data and Groundwater Levels Hourly Hourly Rainfall (mm) 02/03/2007 02:00 02/03/2007 02:00 Hourly Rainfall (mm) Rainfall Hourly 02/03/2007 04:00 02/03/2007 04:00 02/03/2007 06:00 02/03/2007 06:00 02/03/2007 08:00 02/03/2007 08:00 02/03/2007 10:00 02/03/2007 10:00 Date Date Groundwater Level (mAOD) Level Groundwater 02/03/2007 12:00 02/03/2007 12:00 Groundwater Level (mAOD) Level Groundwater 02/03/2007 14:00 02/03/2007 14:00 02/03/2007 16:00 02/03/2007 16:00 02/03/2007 18:00 02/03/2007 18:00 02/03/2007 20:00 02/03/2007 20:00 02/03/2007 22:00 02/03/2007 22:00 03/03/2007 00:00 03/03/2007 00:00 03/03/2007 02:00 03/03/2007 02:00 03/03/2007 04:00 03/03/2007 04:00 03/03/2007 06:00 03/03/2007 06:00 03/03/2007 08:00 03/03/2007 08:00 03/03/2007 10:00 03/03/2007 10:00 03/03/2007 12:00 03/03/2007 12:00 03/03/2007 14:00 03/03/2007 14:00 03/03/2007 16:00 03/03/2007 16:00 03/03/2007 18:00 03/03/2007 18:00 03/03/2007 20:00 03/03/2007 20:00 03/03/2007 22:00 03/03/2007 22:00 0 0.5 1 1.5 2 2.5 3 3.5 04/03/2007 00:00 0 0.5 1 1.5 2 2.5 3 3.5 Rainfall (mm) Rainfall Rainfall (mm) Groundwater Level (mAOD) Groundwater Levels (mAOD) 82.85 82.86 82.86 82.87 82.87 82.88 82.88 84.134 84.136 84.138 84.140 84.142 84.144 84.146 84.148 84.150 84.152 84.154 01/03/2007 00:00 01/03/2007 00:00 01/03/2007 02:00 01/03/2007 02:00 01/03/2007 04:00 01/03/2007 04:00 01/03/2007 06:00 01/03/2007 06:00 01/03/2007 08:00 01/03/2007 08:00 01/03/2007 10:00 01/03/2007 10:00 01/03/2007 12:00 01/03/2007 12:00 01/03/2007 14:00 01/03/2007 14:00 01/03/2007 16:00 01/03/2007 16:00 01/03/2007 18:00 01/03/2007 18:00 01/03/2007 20:00 01/03/2007 20:00 01/03/2007 22:00 01/03/2007 22:00 02/03/2007 00:00 Data BH06and Rainfall Groundwater Levels 02/03/2007 00:00 Data andGroundwaterBH02 Levels Rainfall 02/03/2007 02:00 Hourly Rainfall Hourly (mm) Rainfall 02/03/2007 02:00 02/03/2007 04:00 Hourly Rainfall (mm) Rainfall Hourly 02/03/2007 04:00 02/03/2007 06:00 02/03/2007 06:00 02/03/2007 08:00 02/03/2007 08:00 02/03/2007 10:00 Date 02/03/2007 10:00 02/03/2007 12:00 Groundwater Level (mAOD) Level Groundwater Date 02/03/2007 12:00 02/03/2007 14:00 Groundwater Level (mAOD) Level Groundwater 02/03/2007 14:00 02/03/2007 16:00 02/03/2007 16:00 02/03/2007 18:00 02/03/2007 18:00 02/03/2007 20:00 02/03/2007 20:00 02/03/2007 22:00 02/03/2007 22:00 03/03/2007 00:00 03/03/2007 00:00 03/03/2007 02:00 03/03/2007 02:00 03/03/2007 04:00 03/03/2007 04:00 03/03/2007 06:00 03/03/2007 06:00 03/03/2007 08:00 03/03/2007 08:00 03/03/2007 10:00 03/03/2007 10:00 03/03/2007 12:00 03/03/2007 12:00 03/03/2007 14:00 03/03/2007 14:00 03/03/2007 16:00 03/03/2007 16:00 03/03/2007 18:00 03/03/2007 18:00 03/03/2007 20:00 03/03/2007 20:00 03/03/2007 22:00 03/03/2007 22:00 04/03/2007 00:00 0 0.5 1 1.5 2 2.5 3 3.5 04/03/2007 00:00 (mm) Rainfall 0 0.5 1 1.5 2 2.5 3 3.5 Rainfall (mm) Rainfall 11 Hydrogeology – Groundwater divide • The groundwater contours have identified a groundwater divide • South easterly groundwater flow to the east • Southerly and south westerly flow to the west • Feb 2007 contours Surface water levels • Hitchcopse Pit pond, Cothill Fen and Parsonage Moor. • Continual monitoring data - Water levels in Parsonage Moor are approximately 0.6m higher than those at Cothill Fen. • The fluctuation of surface water levels in Cothill • Fen and Parsonage Moor are small with a range of 0.08m and 0.01m respectively. • The water levels in Hitchcopse Pit pond have been taken from a gauge board installed in the pond and are recorded as fluctuating by approximately 0.095m.