Canadian Cataloguing in Publication

Butcher, G. A. (George Alan), 1952-
Peace River area, Pouce Coupe River sub-basin, water quality assessment and objectives

[Vol. 2] constitutes technical appendix.
ISBN 0-7726-1737-6

1.  Water quality - Pouce Coupe River Watershed (BC and Alta).
I.  British Columbia Environment.  Water Management Division. II.  Title.

TD227.B7B874 1993    363.73'942'0971187    C93-092109-7

TABLE OF CONTENTS

• Canadian Cataloguing in Publication Data
• Figure 1. Pouce Coupe River Sub-basin Map
• Tables
  • Table 1. Provisional Water Quality Objectives for the Pouce Coupe River and Dawson Creek
  • Table 2. Recommended Routine Water Quality Monitoring for Dawson Creek and the Pouce Coupe 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 assessments undertaken during 1983. In general, the study was designed to examine the status of 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 Pouce Coupe River sub-basin.

HYDROLOGY

The seasonal flow pattern is characterized by snowmelt flood peaks from March to June, declining to mid-summer low flows. During the mid-summer low flows, Dawson Creek may dry up except for sewage effluent from the City of Dawson Creek. The Pouce Coupe River also experiences extremely low flows and may almost dry up near the Village of Pouce Coupe. Minimum flows also occur during the winter: both Dawson Creek and the Ppouce Coupe River are completely ice-covered, and Dawson Creek may freeze to the bottom.

There are no existing or known future potential water withdrawals upstream from existing waste discharges that could reduce downstream dilution. Also, there are no existing or future potential withdrawals downstream from the existing waste discharges which would be adversely affected by effluent input.

WATER USES

WASTE DISCHARGES

The Village of Pouce Coupe has a population of 847 (1982) and is predominantly residential in character. The existing treatment system, modified in 1983, consists of two anaerobic cells, two facultative lagoons in series and a large stabilization-storage lagoon. Treated effluent which was discharged on a year-round basis, will now be discharged from April to June. Review of existing effluent monitoring data shows that the treatment system produced good quality effluent relative to the permit issued in 1976. However, during the August and October-April 10-year low flow. effluent dilution can fall below 20:1.

Effluent quality is expected to meet upgraded 1982 permit conditions with an expanded lagoon capacity constructed in 1983. This lagoon will allow year-round storage with discharge during spring flows, April-June. However, continuous effluent discharge during this period does not guarantee 20:1 dilution. During the 10-year low flow for the discharge period, dilution could fall to 10:1. Only careful effluent discharge proportional to available stream flow will provide greater than 20:1 dilution for this period.

The City of Dawson Creek has a population of 11634 (1982) and is mainly residential with some light industry. The sewage treatment facilities consist of a series of two anaerobic lagoons, two aerobic lagoons and one stabilization lagoon discharging to Dawson Creek on a year-round basis via a series of beaver ponds. Discharge is as minimal as possible during winter. Review of effluent monitoring data for the period 1971 to 1982 shows that the system produced high quality effluent relative to permit conditions, although permitted conditions were not consistently met.

WATER QUALITY

One way of ensuring a high dilution of municipal effluent would be to adjust the effluent flow according to the available streamflow. This could be accomplished by installing a staff gauge and developing a stage discharge curve for the Pouce Coupe River at the Village. Municipal staff could then refer to the curve when regulating effluent flow.

Flow in Dawson Creek may completely cease during low flow periods and both past and present waste loads probably result in severe dissolved oxygen depletions, toxic levels of un-ionized ammonia-nitrogen and fecal coliform densities hazardous to human health, rendering the water unsuitable for aquatic life and water contact recreation. Effluent quality is expected to improve in the future with the planned installation of mechanical aeration in 1984.

Aeration is not expected to eliminate the severe water quality degradation projected for Dawson Creek for the next 10 years. Even attainment of the highest quality effluent in keeping with Provincial Effluent Objectives would not eliminate this problem. Alternative treatment and disposal methods which could improve Dawson Creek water quality will need to be investigated. These alternatives include pipelining the effluent to another watercourse, land disposal and advanced treatment.

PROVISIONAL WATER QUALITY OBJECTIVES

The provisional water quality objectives are summarized in Table 1. The objectives are based on preliminary working criteria for water quality and on available data on ambient water quality, waste discharges, water iuses and river flows.

The objectives will remain provisional until receiving water monitoring programs provide adequate data and the Ministry has established approved water quality criteria for the characteristics of concern.

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.

The provisional objectives are probably not being met in Dawson Creek due to the discharge from the City of Dawson Creek. If the objectives are to be met, this municipal effluent must either be given some form of advanced treatment or disposed of elsewhere. In the Pouce Coupe River upstream from Dawson Creek, the provisional objectives are probably not met all year round. One way of achieving the objectives would be to regulate the discharge from the Village of Pouce Coupe according to available streamflow, thereby providing sufficient dilution. In the Pouce Coupe River downstream from Dawson Creek, the objectives are probably frequently not being met. This situation will be corrected when suitable control measures for the municipal discharges are worked out.

MONITORING RECOMMENDATIONS

TABLES