CITY OF PRINCE GEORGE WELLS PROTECTION PLAN

March 2015
City of Prince George Well Protection Plan
o
If possible, in higher potential collision areas, install trenches next to the railway line to
prevent spills from seeping into the aquifer. These trenches should be a few metres from the
railway line and the areas between the railway line and the trenches should be sealed with
bentonite powder and sand (in a 1:3 ratio) to prevent the spills from entering the aquifer.
Emergency plans should be completed for each high and very high risk, including the necessary
groundwater and soil remediation plan for each contaminant spill that might be caused by railway
transportation of chemicals and products. For example, consider installing monitoring wells now to
allow emergency workers to go in and install dewatering pumps, identify or set up areas to which the
water can be pumped, and complete some discharge planning now. Remediation contractors should
be involved in the design of these plans.
The City has designated Groundwater Protection Areas (Figure 19) but the railway tracks are shown
to be on the edge of the Groundwater Protection Areas, and the Nechako River is not included. The
Groundwater Protection Areas are based on modelling during simulated pumping conditions. Given
the consequence of a spill along the railway, a more conservative approach may be in order, than
relying on one groundwater numerical model. We therefore recommend:
Adding a 100 m radius around each well to the City’s Groundwater Protection Area. The BC Ministry
of Health recommends a minimum wellhead protection zone of 100 m radius from a wellhead (BC
Ministry of Health 2010).
Adding the Nechako River to the well protection zone. The Nechako River is a recharge boundary to
groundwater and should therefore be included in the wells’ capture zones. This task will include
hydraulic modelling of the Nechako River to show the limits of the capture zones upstream of the
Nechako River for various time-dependent well protection areas (50-day, 1, year, 5-year, and 20-year
are the groundwater protection area times-of-travel used).
Completing a detailed groundwater flow direction study in two locations: between CN tracks and PW
660, and the CN track and PW 605. The modelled capture zones show that the 60-day capture zone
extends past the CN tracks; however, the limitations of Golder’s report (2003) included some
uncertainty with groundwater flow direction and hydraulic gradients “especially at greater distances
from the river”. Installing dataloggers in monitoring wells and a water level monitoring station in the
Nechako River, and tracking water levels for at least one year, will help assess actual groundwater
flow in these two key areas; and
Updating the numerical flow model to assess the capture zones specifically in the vicinity of the CN rail
tracks, once actual groundwater and surface water levels in these two areas have been monitored.
Given that models are based on assumptions, an independent review of the numerical model may
also be prudent.
Page | 53