TABLE OF CONTENTS

• Figure 1. Pine River Sub-basin Map
• Tables
  • Table 1. Provisional Water Quality Objectives for the Pine River
  • Table 2. Recommended Routine Water Quality Monitoring for the Pine River
• Preface
• Introduction
• Hydrology and Oceanography
• Water Uses
• Waste Discharges
• Water Quality
• Provisional Water Quality Objectives
• Monitoring Recommendations

PREFACE

Water quality objectives are prepared for specific bodies of fresh, estuarine and coastal marine surface waters of British Columbia as part of the Ministry of Environment, Lands and Parks' mandate to manage water quality. Objectives are prepared only for those waterbodies and water quality characteristics that may be affected by human activity now or in the near future.

Water quality objectives are based the BC approved and working criteria as well as national water quality guidelines. Water quality criteria and guidelines are safe limits of the physical, chemical, or biological characteristics of water, biota (plant and animal life) or sediment which protect water use. Objectives are established in British Columbia for waterbodies on a site-specific basis. They are derived from the criteria by considering local water quality, water uses, water movement, waste discharges, and socio-economic factors.

Water quality objectives are set to protect the most sensitive designated water use at a specific location. A designated water use is one that is protected in a given location and is one of the following:

• raw drinking water, public water supply, and food processing
• aquatic life and wildlife
• agriculture (livestock watering and irrigation)
• recreation and aesthetics
• industrial water supplies.

Each objective for a location may be based on the protection of a different water use, depending on the uses that are most sensitive to the physical, chemical or biological characteristics affecting that waterbody.

Water quality objectives routinely provide policy direction for resource managers for the protection of water uses in specific waterbodies. Objectives guide the evaluation of water quality, the issuing of permits, licences and orders, and the management of fisheries and the province's land base. They also provide a reference against which the state of water quality in a particular waterbody can be checked, and help to determine whether basin-wide water quality studies should be initiated.

Water quality objectives are also a standard for assessing the Ministry's performance in protecting water uses. While water quality objectives have no legal standing and are not directly enforced, these objectives become legally enforceable when included as a requirement of a permit, licence, order, or regulation, such as the Forest Practices Code Act, Water Act regulations or Waste Management Act regulations.

Water quality objectives are established to protect all uses which may take place in a waterbody. Monitoring (sometimes called sampling) is undertaken to determine if all the designated water uses are being protected. The monitoring usually takes place at a critical time when a water quality specialist has determined that the water quality objectives may not be met. It is assumed that if all designated water uses are protected at the critical time, then they also will be protected at other times when the threat is less.

The monitoring usually takes place during a five week period, which allows the specialists to measure the worst, as well as the average condition in the water.

For some waterbodies, the monitoring period and frequency may vary, depending upon the nature of the problem, severity of threats to designated water uses, and the way the objectives are expressed (i.e., mean value, maximum value).

INTRODUCTION

This report is the product of data evaluations undertaken during 1983. In general, the study was designed to examine the status of existing and future water quality with respect to existing and future water uses and waste discharges. Included in this report are provisional water quality objectives to protect designated water uses and a recommended monitoring program. The goal of this assessment is to guide water and waste management in the Pine River mainstem.

HYDROLOGY

The hydrologic cycle in the Pine River is characterized by lowest flows during the winter months, peak flows during the spring and declining flows in the late summer. The extreme low flows (7-day average, 10-year return period) expected in the Pine River near Chetwynd are 4.7 m³/s during midwinter and 21 m³/s during August.

WATER USES

The Pine River mainstem supports significant sportfish populations requiring water quality protection. Recreational use of the Pine River includes angling and boating. Swimming is not known to occur in the Pine River to any significant extent.

WASTE DISCHARGES

The major influence on Pine River water quality is the year-round discharge of treated sewage (3000m³/d or 0.035 m³/s) from the Village of Chetwynd. Effluent monitoring data for this discharge show that the treatment system generally produced good quality effluent in compliance with permit conditions. Available water quality data did not show any serious impairment of water quality although the data base was not adequate to provide a good analysis of the situation. Additionally, the site of the outfall was changed from Centurion Creek to the Pine River and there are presently few data analyzing its direct effect on the river.

The Westcoast Transmission Co. Ltd. natural gas processing plant at Hasler Flats emits contaminants into the air from the sweetening of natural gas. Contaminants include NO_x, SO_x and H₂S. The effects of these acidic contaminants on the Pine River watershed have not been measured but are not expected to be significant. Reliable precipitation and pH data are required to assess fully whether acid precipitation is a regional problem.

The small underground coalmine (0.6 million tonnes per year) proposed for Willow Creek by David Minerals Ltd. is not expected to degrade the water quality of the Pine River. The mine does not entail extensive terrain disturbance not will there be any preparation or washing of the coal product. A water management plan which includes diversion ditches and a series of settling ponds should ensure that discharged wastewatwer will meet Provincial effluent objectives for suspended solids, the only constituent of concern for this project. Presently, the mine proposal is on indefinite hold due to depressed market conditions.

The Westcoast Transmission Co. Ltd. Willow Flats subdivision consists of 15 houses discharging domestic effluent into a lagoon system. Monitoring data for this discharge show that effluent characteristics generally exceeded permitted levels, although the number of samples was small. The Willow Flats subdivision has discharged treated sewage to the Pine River only once since the issuance of the permit in 1971. Given the high dilution available in the Pine River, and the intermittent nature of this small discharge, no degradation of water quality is expected.

WATER QUALITY

Effluent dilution will remain above 60:1 even during severe winter low flows. There is, however, evidence that sewage input from Chetwynd is altering the natural nutrient balance in the Pine River. Phosphorus levels in August, downstream from Chetwynd, are projected to be double ambient concentrations and the nitrogen:phosphorus ratio is predicted to be 5:1 under certain conditions. At these projected nutrient levels algal growth could reach nuisance proportions over the next 10 years, downstream from the Chetwynd outfall. Excess growth of periphyton could affect the fish population in several ways: by smothering spawning substrates, by reducing food availability and by localized dissolved oxygen reductions.

Fecal coliform concentrations in the Pine River are projected to be 26 to 40 MPN/100 mL during the August low flow and 4000 MPN/mL during the winter low flow, under present conditions of maximum effluent flow and maximum effluent concentration. Future concentrations are projected to range for 684 to 4654 MPN/100 mL for the same low flow periods. Some of these levels exceed the BC Ministry of Health criterion for primary contact recreational waters, (i.e., 200 to 400/100 mL).

PROVISIONAL WATER QUALITY OBJECTIVES

The objectives can be considered as policy guidelines for resource managers to protect water uses in the specified water bodies. For example, they can be used to draw up waste management permits and plans, regulate water use or plan fisheries management. They can also provide a reference against which the state of water quality in a particular water body can be checked.

Water quality objectives have no legal standing and their direct enforcement would not be practical. This would be due to the difficulty of accurately measuring contaminants in receiving water and attributing the contamination exceeding the objective to particular sources for legal purposes, and thus of proving violations and their causes. Hence, although water quality objectives should be used when determining effluent permit limits, they should not be incorporated as part of the conditions in a waste management permit.

Depending on the circumstances, water quality objectives may already be met in a water body, or may describe water quality conditions which can be met in the future. To limit the scope of the work, objectives are only being prepared for water bodies and water quality characteristics which may be affected by man's activities, now and in the foreseeable future.

Provisional water quality objectives are summarized in Table 1. They apply to discrete samples taken at any time, at any point in the river, either upstream or downstream from Chetwynd, but outside the initial dilution zone of a waste discharge. The objectives apply-year round except for the fecal coliforn objectives downstream from Chetwynd which apply only during the recreation season (June to September inclusive).

Samples to check coliform and nitrogen objectives are taken over a 30-day period at weekly intervals. This frequency would only be used if less frequent routine monitoring or other factors suggested that the objectives may be exceeded.

a) Upstream from Chetwynd
Upstream from Chetwynd there is the potential for elevated levels of suspended solids and turbidity originating from the Willow Creek Coal Project and for elevated levels of fecal coliform bacteria from the West Coast Transmission Co. Ltd. Willow Flats subdivision effluent. Although it is unlikely that either discharge would impact the Pine River water quality it is proposed that the following designated water uses be protected: drinking water supplies (Westcoast Transmission Co, Ltd. Willow Flats subdivision, Village of Chetwynd), recreation (i.e., canoeing, swimming, angling) and aquatic life. The provisional objectives appear to be met according to the few data available.

b) Downstream from Chetwynd
Downstream from the Chetwynd municipal discharge there is the potential for depressed levels of dissolved oxygen and for elevated levels of suspended solids, turbidity, un-ionized ammonia-nitrogen, fecal coliform bacteria and nutrients. Although there is high effluent dilution available even during low flow periods, significant increases in the above constituents are possible outside the initial dilution zone before complete mixing occurs. Water quality objectives are recommended to protect the following designated water uses: recreation (i.e., canoeing, swimming, angling) and aquatic life.

Downstream from Chetwynd projections of present effluent concentration suggest problems with nutrients and fecal coliform bacteria although there are no water quality data to confirm this. Future growth of Chetwynd's population could increase coliform levels and algal growth at points downstream.

MONITORING RECOMMENDATIONS

A fish sampling program is also recommended in the vicinity of present and potential effluent discharges. This sampling would determine fish species distribution and habitat use in the Pine River mainstem for the purpose of gaining information on the value of the resource to be protected.

It would be useful if a gauging station were established on the Pine River at the Chetwynd outfall to substantiate the low flow estimates used to preduct effluent dilution ratios.

TABLES