Appendix A

Long Valley - Action Plan for Potential Changes in Groundwater Regime or Surface Settlement during Construction

(Extracted from Table 3.3 of the EIA Report)

Prescriptive Action	Available Measures
Pre-emptive	Install a suite of piezometers (4 pairs) that straddle the tunnel alignment and monitor groundwater cycles for 24hr periods during peak Spring and Lowest Neap tide cycles at the beginning and end of the Wet and Dry Seasons throughout the year preceeding tunnel construction. Undertake additional monitoring cycles to cover unusual periods of activity such as the passage of a major storm and flood event or the prolonged operation of the downstream fabridam so as to exclude tidal variation. Consult the District Council and establish a Long Valley Action Committee amongst the working farmers to keep them informed at all times of works progress and agree an Event Action Plan. Clean out main channel serviced by Agriculture, Fisheries and Conservation Department (AFCD) fabridam and downstream watercourse. Pre-empt any problems with the main mid-Long Valley watercourse through inspection, cleaning of accumulated silt and re-inforcement of known weak points and sharp changes of direction. Set up a planned Contingency Agreement and Action Plan with AFCD and Water Services Department so that the full benefits of the installed fabridams can brought to bear promptly should the need ever arise.  Work with AFCD to increase the degree of inflation of the River Beas Fabridam so as to be able to divert more flow into Long Valley and carry out a trial run of same checking the influence and performance downstream within Long Valley. Upon commencement of tunnelling, work with the local farmers to raise and reinforce bund levels by 100mm at all points where the mid-Long Valley watercourse traverses a tunnel alignment.
Response to observed changes in the ground conditions and significant measured changes in the control piezometers	In consultation with the farmers, increase available irrigation flows originating at the AFCD fabridam by resetting sluice levels at the take off point and adjusting the proportions of the downstream bypass overflows back to the Beas. Pump over from the Beas or Sutlej rivers into the larger seasonal watercourses to make up any continuing water shortfall, should such occur. This could include pumping up to the main AFCD irrigation channel as was done during the period of construction of the drainage improvement project on Beas and Sutlej Channels carried out by the Drainage Services Department (DSD). Work with the farmers to supply and stockpile materials suitable for local bund raising should the need occur. New sandbags to be stored on site ready for issue. Additional pumps and flexible delivery hose to be provided on stand- by. Arrange additional pumping to maintain continuous but moderate flows in the normally dry irrigation channels, delivering water throughout the complicated channel network across the tunnel alignment including possible local recharge of disused wells.
Additional Actions available to combat an emergency	To overcome a worst case scenario of a temporary general lowering of the groundwater raise the downstream fabridam operated by Water Services Department (WSD) to impound the Beas, Sutlej and Indus rivers flooding the alluvial aquifer across the Long Valley floor to temporarily create the effect of a standing high tide or surge. This form of impounding is a permanent design function of the WSD fabridam, albeit implemented for a non WSD purpose.