Hatfield Consultants
March 2016
Executive Summary
This document outlines the development of a screening tool to identify lake withdrawal limits that have a low risk of unacceptable environmental effects.
This preliminary tool was developed following a review of methodologies used in other jurisdictions, current environmental considerations for Alberta and British Columbia water license applications, and available hydrologic data.
The tool allows proponents to determine conservative lake withdrawal volumes and lake level drawdown limits. The approach is designed to be applicable to gauged and ungauged lakes greater than 0.1 km2 in size and located within Alberta and Northeast BC. The approach is intended to be primarily desktop-based, but may use site-specific data (if available). The tool may be used to quickly steer a proponent away from areas where withdrawals may pose a higher risk, and towards more hydrologically favourable lakes (e.g., lakes with greater volume, depth and runoff). The tool uses publicly available hydroclimatic datasets, and preliminary datasets have been created where suitable ones were not previously available.
The screening tool is based on four main considerations:
Multiple approaches to address these considerations and answer these questions were considered during the development of the tool. These approaches were assessed to determine which considerations were likely to be limiting (i.e., which considerations resulted in the most conservative withdrawal criteria), and those limiting criteria were consolidated into a simple set of withdrawal limits. Proposed withdrawals that are below the proposed coarse screening limits are anticipated to have a lower likelihood for unacceptable environmental impacts.
Proposed withdrawals that exceed the withdrawal limits in this tool may still pose a low risk to environmental values; however, additional, site-specific information is required to more accurately assess potential impacts under these circumstances.
# 15-WIPC-06