Innovation-March_April 2013

system and likely subsurface karst conditions. Any notable surface karst features including cave entrances, springs or sinkholes require assessment for their potential significance. This is done in a qualitative manner considering criteria such as: dimensional characteristics, connectivity, rarity or abundance, visual quality, and geological, hydrological, biological, scientific/educational, archaeological/cultural and recreational/commercial values. The four-step Karst Vulnerability Assessment Procedure detailed in the KISVAP document is used to assess the broader karst landscape (the land encompassing the individual surface karst features) and stratifies the site of interest (e.g., a proposed logging area) into smaller map areas or polygons having low, moderate, high or very high karst vulnerability. Careful examination of streams, where water flows onto a karst unit is commonly required, and more so where they disap- pear at sink points. In some cases techniques such as dye tracing are used to delineate recharge areas and subsurface flow paths— particularly where sensitive downstream resources are known to exist. Karst catchments can extend beneath surface drainage divides, making them more difficult to define and in some cases of much greater extent than might otherwise be anticipated. Caves and their resource contents/values should be inves- tigated and evaluated. Surveys are often required to establish the location of cave passages and chambers in relation to the surface within the development area of interest. Cave environ- ments can be very sensitive to disturbance and some caves can pose a safety risk. Karst management strategies (or best practices) for road building, timber harvesting and any planned post-harvest treatments are then developed for: individual karst features, surface streams draining onto the karst, and the broader karst

A proposed wind turbine generation site on a forested karst plateau in northern Vancouver Island was assessed in 2002. This karst plateau included an area of large, well-formed sinkholes with an associated subsurface drainage system. An assessment was required to determine how the placement of the wind tur- bines, their clearance areas, the associated connecting transmis- sion line corridors, and the reactivation of old logging roads for access might impact the karst landscape. In 2004, a small hydroelectric power project in northwestern Vancouver Island required a karst evaluation in its early stages to determine how the transmission line corridor, intake struc- ture and powerhouse might affect karst landscapes. Concerns included the potential impacts of routing the transmission line through high vulnerability subalpine karst and the stability of planned structures. In 2007, a small hydroelectric power project in northern Vancouver Island proposed linking Victoria Lake to Neroutsos Inlet with a tunnel. Key concerns in this case were related to the potential intersection of karst voids (filled or unfilled) and/or encountering subsurface flows during tunnel construction. Field techniques used included detailed structural geological mapping and the identifica- tion of surface karst features indicative of karst processes. Quarrying or mining limestone and dolomite is not unusual in BC as both materials are used commercially for a wide variety of products; however, the potential impact of these activities on karst resources is occasionally overlooked. Concerns can include: disruption and contamination of karst groundwater, encounter- ing large karst cavities (which may or may not have significant values), and impacts to karst ecosystems or other values. Mineral exploration and mining activities within BC can also be located on or close to carbonate bedrock that may have developed karst.

landscape. Best management prac- tices recommended for forested karst lands in BC are found in the KMH. Other strategies and measures may be employed based on experience and site conditions, provided that the desired objectives are met and in compliance with any legal requirement. Examples of Other Projects and Activities on Karst Lands Many of the assessment techniques and management strategies used for forestry on karst landscapes have applications for other types of activities on or near karst lands. These other activities could include: renewable energy projects, quarries, mining sites, oil and gas activi- ties, parks and recreation areas, special waste sites, landfills or water supply areas. Many of these projects typically require the construction/upgrading of access roads, vegetation clearance and the installation of various types of infra- structure. A number of case examples are outlined below.

Bull Housser’s lawyers have been trusted to handle some of the largest developments and transactions in British Columbia’s history. Today we have more than 30 areas of expertise, including core BC industries and specialty areas, and remain focused on reaching effective resolutions for our clients. We apply creative approaches to deliver solutions that are practical and cost-efficient. We’ve been around for over a century, but we’re just getting started...

19

M a r ch/A p r i l 2 013

i n n o v a t i o n