Canadian Cataloguing in Publication Data

Nordin, Richard Nels, 1947-
Thompson River water quality assessment and objectives

[Vol. 2]
ISBN 0-7726-1708-2

1.  Water quality - British Columbia - Thompson River.
I. Holmes, Donald W.  II. BC Environment.  Water Management Division.
II.  Title.  III. Title.


TD227.B7N67 1993    363.73'9420971172    C93-092081-3

TABLE OF CONTENTS

• Canadian Cataloguing in Publication Data
• Thompson River Location Map
• Tables
  • Table 1. Provisional Water Quality Objectives for the Thompson River
  • Table 2. Resin Acid Water Quality Objective Concentrations
• Introduction
• The South Thompson River
• The North Thompson River
• Thompson River Above Kamloops Lake
• Kamloops Lake
• The Lower Thompson River

INTRODUCTION

In general, the water quality of the mainstem Thompson is relatively good although there have been, in some cases, significant impacts from municipal or industrial discharges as well as from non-point inputs. Water uses have been identified and water quality objectives set for characteristics such as microbial indicators, colour, chlorinated organics and resin acids in various reaches of the Thompson to provide a basis for future water quality protection and management.

The South Thompson River

The water quality of the South Thompson, on the basis of the data collected over the past 20 years, is relatively good and no strong evidence couls be found for trends of water quality deterioration over the period for most characteristics. The characteristic for which some concern is noted is the microbiological quality of the water, probably originating from non-point discharges. Water quality objectives for this characteristic are proposed.

The North Thompson River

The Thompson River Above Kamloops Lake

The other major discharge to the system is the Weyerhaeuser bleached kraft pulp mill. The components of the discharge which are of concern are nutrients, colour, and chlorinated organics. Over the period of record, improvements have been made in all of these areas but concerns still remain as to the effects of these and other discharge components. Increasing production, in some cases, has reduced the net effectiveness of the improvements made in effluent quality by increasing the overall amount of these discharge components. There are few ambient water quality data available for this section of the river because of the difficulties in obtaining representative samples.

Water quality objectives in this section of the river include microbiological indicators to protect the water for use as drinking water supply and for recreational use, objectives for clour, chlorinated dioxins and furans (in water, sediments and in fish tissue) and resin acids. In this section of the river channel there is very little mixing of the separate contributions of river flow from the North and Soputh Thompson. They remain distinct at least until they reach Kamloops Lake. Because of the flow pattern, the discharges from the two major wastewater sources at times of low flow are not dispersed quickly into the river and in the case of the pulp mill can be readily seen as a discrete plume of effluent along the south shore of the river. The objectives proposed are to apply to an area outside the initial dilution zoine which is defined as being 100 metres downstream of the points of discharge. For one objective, colour, the objective proposed is a long term one which will probably not be met in the short term.

Kamloops Lake

The Lower Thompson River

Considerable public and government concern has been directed to potential contaminants from the Kamloops pulp mill, particularly dioxins and furans. Recent studies have examined the amounts of these contaminants in fish tissues, river sediments and water. As a result of these and previous studies, some Ministry of Health consumption advisories have been issued. Recent improvements at the pulp mill have resulted in reduced amounts of discharges of these compounds of concern.

The problem of heavy attached algal biomass in the lower Thompson, sampled at Savona and Walhachin, is discussed in the technical appendix in relationship to trends in nutrient supply and other causal factors. On the basis of recommendations of a Federal-Provincial study in 1975, inputs of phosphorus were reduced from the City of Kamloops. Although the data base is poor, it appears that the amount of attached algae has also been reduced from the obvious problem levels of the early 1970's. However, over the time period examined, phosphorus inputs have decreased, and then gradually increased, without any corresponding increase in algal biomass. These data, along with research data published by Environment Canada, indicate that nutrient input/or concentration may not be the only factors controlling algal biomass in the Thompson and that invertebrate grazers and other factors may play a role in determining algal biomass.

In this reach of the river there are water quality objectives set for microbiological indicators, colour, chlorinated dioxins and furans and resin acids. As well, there is an objective set for attached algal biomass as a means of protecting the aesthetic attributes of this section of the river.

TABLES