The Kawesas Watershed Assessment

I: Introduction

Peter K. Schoonmaker

The 40,494-hectare Kawesas watershed is part of the Greater Kitlope Ecosystem (Map 2). The river flows into the Kawesas estuary which flows into the Gardner Canal. In many ways the Kawesas is typical of mid-sized glacially carved valleys on B.C.'s north coast. The U-shaped valley walls rise steeply to glacier-covered peaks that approach 2,000 metres. Rockfalls, slide areas, snow avalanches, and debris flows send large pulses of sediment to the valley floor where it reshapes the path of the river.

The cool, wet climate produces a prodigious snowpack, and results in extremely high river flows on the 26-kilometre main-stem of the Kawesas in the fall and the spring; late summer flows can be quite low. These flows are constricted in several places as the valley bottom is generally less than 500 metres across, widening to 1 km only below Cole Creek (5 km from the river mouth). Four species of salmon are known to spawn in the Kawesas; high quality habitat occurs from the estuary to 26 km upstream, where two main forks descend down waterfalls, blocking migration for all salmonids. Oolichan spawn in the lower reaches.

The abundant rainfall also supports forests of western hemlock, amabilis fir, western red cedar, and Sitka spruce. Stands of cedar usually include one or more trees which were modified by aboriginal use, often hundreds of years ago. The vegetation provides structure in the aquatic system as large woody debris, creating a series of rapids and pools and stabilizing a naturally dynamic river. For thousands of years the river has excavated its bed back and forth across the valley floor, playing out a dynamic counterpoint of destruction and renewal with floodplain forest.

Fish and wildlife abundance follow predictable seasonal patterns. For example, mountain goats can be seen down on river beaches in March, and move up the slopes as the summer progresses. Bears roam the meadows for early spring vegetation and are found at feeding spots along the river in the late summer and fall when the salmon are spawning. Cultural and physical evidence indicates that these patterns of abundance have supported Haisla people for millennia.

Objectives

The initial motivation for undertaking this watershed assessment was the Haisla Nations concern that future five-year plans would assume timber harvest was the highest (and only) use for the Kawesas. This assessment builds on five years of association between the Haisla and Ecotrust, and represents a refinement of previous efforts (Travers 1991, Schoonmaker and Kellogg 1993, Haisla Nation 1993), using an emerging tool — watershed assessment — to synthesize scientifically credible ecological and cultural information for an important part of Haisla traditional territory. Most of this report was completed independently of and before West Fraser Timber Co. presented a five-year plan in May 1996 that proposes a 26-hectare cut-block and a 10 km road for the Kawesas. While long-term plans for the Kawesas have not fully been revealed, the information gathered during this study allows us to briefly evaluate the implications of the five-year plan, which we summarize at the center of this document.

Our effort in the Kawesas watershed really consists of two paths, very much interrelated. First, we have produced this watershed assessment. We have assembled information and attempted to understand relationships — especially those between upland and riparian habitats. We have produced a profile of a watershed. Our goal is to increase our understanding of how the Kawesas watershed functions as a system.

The second path relates to planning. The inadequacies of the current regional planning process have been described in the foreword. Now, with the benefit of this assessment the Haisla Nation will be able to go forward to another phase, to propose sustainable, long-term (>100 years) actions based on this assessment, on public involvement, and on more site specific studies where needed. The development of the sort of information we have prepared for the Kawesas should be pertinent and useful for all parties involved in the ongoing treaty making process. It may also provide a model for the development of watershed assessment methodologies that could be used in other watersheds on the coast of British Columbia. Another benefit of this project has been the establishment of baseline information for a representative pristine watershed. This information should be useful to those wishing to restore the ecological integrity of watersheds, for example the Watershed Restoration Program, a component of the British Columbia Forest Renewal Plan.

This report is not meant to be the final word on forest harvesting in the Kawesas Valley, but it provides the Haisla Nation and others with some of the information needed to reach an informed decision about resource management in the Kawesas. In that spirit, we present information about characteristics of the watershed and the impacts that logging may have on them. We also briefly evaluate other possible uses of the valley and further suggest specific reasons why the intact Kawesas represents an important resource.

Methods

We have used a modified watershed assessment methodology to gather information for guiding ecosystem management for the Kawesas watershed. This methodology should be helpful to various ministries and organizations in British Columbia because it is tailored to assess pristine watersheds and is based on current watershed assessment procedures. The Kawesas assessment follows methodology of the Coastal Watershed Assessment Procedure (B.C. Ministry of Forests 1995), emphasizing pre-fieldwork data collection and analysis, field studies focused on ground-truthing a subset of the database, and surveying for key ecological characteristics. Field methods were designed to be replicable so that this initial effort can be utilized as the baseline for a long-term monitoring program.

This watershed assessment effort began by assembling available information (aerial photographs, digital elevation [TRIM] maps, geologic maps, forest cover, fish abundance, wildlife species abundance, cultural information, current harvest plans, etc.) about the Kawesas watershed into a geographic information system (GIS) database. This allowed scientists to identify information gaps that required field work. The 1995 field season centered on mid to late summer (with the exception of oolichan and salmonid counts, which were staggered throughout the year). The field data for each module were collected in less than two weeks of field time, except for salmon enumeration and wildlife assessment. We restricted most of our field work to the productive forest area below 300 m elevation and concentrated in particular on three key areas: the main forks of the river about 26 km from the mouth (west of Marmot Peak); the middle area near the confluence with Cole Creek; and the lower area within 2 km of the estuary (which is likely the highest in biodiversity values).

This assessment is arranged into this introduction, six chapters that describe field work and results, and a conclusion containing a summary of key findings. The six chapters at the heart of the assessment are as follows:

Chapter 1. We begin with general climate and geological profiles, factors which drive all biological processes. We then explore the attributes of rock and soil that form the substrate for plant and animal communities of the Kawesas, concluding with analyses of the consequences of disrupting this substrate through commercial timber harvesting. Most of the map work for this chapter is based on air photos and topographic maps, with about two weeks of field work to ground-truth the terrain analysis.

Chapter 2. Using forest cover maps and vegetation plots, we present an overview of Kawesas Valley vegetation, the component of the watershed that supplies all other organisms with energy and habitat, and that supplies the river system with much of its structure. We also identify the locations of the most commercially valuable timber stands, and discuss the consequences of harvesting these stands. Chapter 3. We document the distribution and abundance of salmon through Department of Fisheries and Oceans (DFO) records (for adult spawners) and through field sampling (of juveniles). In this chapter we also examine salmonid habitat, which to a great extent is determined by terrain (Chapter 1) as modified by vegetation (Chapter 2), especially fallen logs anchored in the streambed. We discuss the area of riparian forest needed to supply large logs needed to maintain current stream structure over the long term.

Chapter 4. Here we characterize the organisms that occupy the base of the food pyramid in the Kawesas River, the benthic invertebrates. Not only do these animals transfer energy from plants to salmon, they are also excellent indicators of overall watershed health.

Chapter 5. We move from micro- to macro-wildlife in this chapter, focusing on vertebrates that depend to some degree on all the attributes discussed in the previous chapters — terrain, vegetation, aquatic habitat and salmonids, and indirectly, benthic invertebrates. We focus especially on a few large mammals (bear, moose, deer, and goats), on the recently Red Listed marbled murrelet, and on oolichan, one of the foundations of Haisla subsistence and culture, and we conclude with recommendations for the sustainable management of these resources.

Chapter 6. Here we describe how humans have subsisted in the Kawesas for generations, using the plant and animal resources of the watershed without over-exploiting them. Physical evidence — plank and bark scars on trees, charcoal from past dwellings — and oral histories attest to the long history of sustainable use in the Kawesas.

We conclude with a brief summary of key findings and considerations of various watershed management options in light of the Kawesas' ecological and cultural characteristics, and we comment on the current process for managing the Kawesas ecosystem.

Note; All UTM locations given in this report refer to Zone 9; reference maps for the Kawesas watershed include Gardner Canal 103 H/8, Edition 2 and Khutze River 103 H/l, Edition 2, published by the Canada Centre for Mapping, Department of Energy, Mines, and Resources (Ottawa).

Why watershed assessment?

Watershed assessment is emerging as one of the key tools for managing ecosystems in the Pacific Northwest region of North America (Grant et al. 1994). The methodology is a response to widespread concern about the cumulative effects of forest harvesting on water resource quality (Montgomery et al. 1995). It reflects a growing realization that the ecological processes and functions of biotically diverse stream habitats are closely tied to up-slope physical and biological processes.

Watershed assessment is currently used as a prescriptive/regulatory tool in the state of Washington and the province of British Columbia, and as a management/planning tool by U.S. federal agencies (B.C. Ministry of Forests 1995, Washington Forest Practices Board 1995, USDA Forest Service et al. 1994). To date this methodology has been used solely by large agencies and corporations. Full field implementation has proven to be too expensive ($250,000 to $1,000,000 per watershed) for community-based organizations. Watershed assessment that is limited to compiling existing data on a geographic information system (GIS) ($50,000–$100,000) is unsatisfactory for remote areas that are lacking in basic environmental data such as terrain stability, forest resources, and species presence and abundance.

The utility of watershed assessment for conserving pristine systems has yet to be explored. Watershed assessment is required for guiding forest harvest activities in British Columbia, but has been employed principally for previously harvested watersheds. We know of no watershed assessments that have been completed on unharvested watersheds in British Columbia, although several studies have focused on the probable effect of forest harvesting on landscape stability and channel morphology in pristine watersheds (e.g. Kellerhals 1993). Other studies have examined environmental resource values (e.g. fish, wildlife, old-growth habitat) in pristine watersheds (Moore 1992, Moore 1993). We believe this is the first study to combine the geomorphic information of a watershed assessment with biological (wildlife, fisheries, vegetation, disturbance) and cultural information to produce a comprehensive characterization of a pristine watershed and then analyze likely outcomes of forest harvesting. Other watershed assessments have included more information, but we feel that few have developed procedures that maximize understanding while minimizing conceptual clutter

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