Canadian Cataloguing in Publication Data

Swain, L. G. (Leslie Grant), 1950-
Water quality assessment and objectives for tributaries to Okanagan Lake
near Vernon (Lower Vernon, Equesis and Deep Creeks) Okanagan area

Report prepared by L. G. Swain p. 12
Prepared pursuant to Section 2(e) of the Environment Management Act, 1981
Consists of two parts: An overview and a report, of which the overview is also
available as a separate document. cf. P. 3.
ISBN 0-7726-2017-2

1.  Water quality - British Columbia - Okanagan Valley.
I.  BC Environment.  Water Quality Branch. II.  Title.


TD227.B7S84 1993    363.73'942'097115    C94-0960035-0

TABLE OF CONTENTS

• Canadian Cataloguing in Publication Data
• Summary
• Figure 1. Location Map for the Okanagan Lake tributaries near Vernon.
• Tables Water Quality Objectives and Monitoring Tables
  • Table 1. Water Quality Objectives for Deep Creek and Lower Vernon Creek
  • Table 2. Maximum Concentration of Total Ammonia Nitrogen for the Protection of Aquatic Life
  • Table 3. Average 30-day Concentration of Total Ammonia Nitrogen for the Protection of Aquatic Life
  • Table 4. Maximum and 30-day Average Nitrite (N) Concentration to Protect Aquatic Life
  • Table 5. Recommended Water Quality Monitoring for Deep Creek and Vernon Creek
• Preface
• Introduction
• Hydrology
• Water Use
• Waste Water Discharges
• Water Quality Assessment
• Water Quality Objectives
• Monitoring Recommendations
• Glossary

SUMMARY

Salmonid species are present in lower Vernon, Deep, and Equesis creeks, and the water quality objectives in this report are to form part of a fisheries management plan for tributaries to Okanagan Lake.

Most water contamination comes from the City of Armstrong sewage discharge into Deep Creek, non-point source discharges to Deep Creek and lower Vernon Creek, and possible ground water contamination in some areas from irrigation with treated sewage. The City of Armstrong began a program of spray irrigation of treated sewage in the Spring of 1993, so that discharges to the creek should now only take place during periods of high precipitation.

Water quality objectives are recommended to protect aquatic life, wildlife, irrigation water supplies, and drinking water supplies in Deep Creek and lower Vernon Creek. Water quality objectives were not set for Equesis Creek since there were no known anthropogenic inputs which could impact ambient water quality significantly.

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

TRIBUTARIES TO OKANAGAN LAKE NEAR VERNON-PROFILE

HYDROLOGY

Seven-day low flows have ranged from 0.031 to 0.356 m³/s in the summer and from 0.034 to 0.402 m³/s in the winter in Equesis Creek, from 0.027 to 0.261 m³/s in Deep Creek (usually in August), and from 0.071 to 0.562 m³/s in lower Vernon Creek. All these flows were recorded at sites in the waterbodies located near their confluence with Okanagan Lake. Return periods could not be calculated for these low flows due to incomplete data bases.

WATER USE

Equesis Creek has a large quantity of accessible habitat which would allow for habitat enhancement. Kokanee cannot access the creek beyond the first 2.6 km due to a dam. Larger rainbow trout can pass this dam, but are blocked by a second dam 3.7 km from the lake. The first 5.6 km of Equesis Creek are on reserve lands of First Nations people and complete information on fish usage in this area is not available. In Deep Creek, kokanee have not been documented as being present, and there are no real opportunities to enhance salmonid production in the lower creek. Coarse fish are plentiful in the creek below Armstrong, although there is potential to improve rainbow trout production above Armstrong.

In lower Vernon Creek, rainbow trout, kokanee, peamouth chub, carp, largescale suckers, redside shiners, squawfish, and chiselmouth are known to reside. In addition, juvenile lake trout may be using the creek as a downstream migration corridor since lake trout are beginning to be caught in Okanagan Lake (which has never been stocked with this species). The dam at the end of Kalamalka Lake prevents all species from migrating from Okanagan Lake into Kalamalka Lake. A number of enhancement projects have been undertaken by numerous groups which have improved fish access, habitat potentials, and fish populations.

WASTE WATER DISCHARGES

Other permitted waste discharges within the Deep Creek watershed are the discharge of cooling water from a cheddar cheese manufacturing plant into Deep Creek, and a small-volume discharge from a rendering plant into a seepage pit. This latter operation also has a permitted refuse site.

In the lower Vernon Creek watershed, there are three permitted waste discharges. Two are located near a tributary to lower Vernon Creek, BX Creek, while the Vernon Sewage Treatment Plant is located adjacent to lower Vernon Creek. The treated effluent from the City of Vernon is spray-irrigated on adjacent properties, although an effluent outfall into Okanagan Lake has been built so that waste water can be discharged to the lake (with chemical phosphorus removal) in extremely wet years. It is apparent that the irrigation is causing some nutrients to increase in the ground water at some sites. The City of Vernon Recreation complex discharges cooling water to BX Creek, while a ready-mix cement operation discharges truck wash water to an exfiltration pit.

Non-point sources are also impacting water quality, especially in Deep Creek. A two-year study conducted in 1987 and 1988 on Deep Creek showed that there was an increase of over 4 kg phosphorus per kilometre at sites upstream from Armstrong, presumably due to non-point sources. Downstream from Armstrong (and downstream from Otter Lake), the increase was 105 kg/km. Otter Lake seems to act as a reservoir for nutrients, storing them during low flow periods, and releasing them during high flows. As such, the loadings to Okanagan Lake are concentrated during the high runoff period of the year. Similar impacts likely would be apparent for nitrogen compounds and possibly bacteria concentrations if these phosphorus loadings originated from cattle wastes. It is suspected that phosphorus loadings could originate from several sources, including breakthrough from manure applications due to over-application and peat oxidation in the upper creek valley.

WATER QUALITY ASSESSMENT AND OBJECTIVES

WATER QUALITY ASSESSMENT

Deep Creek is well-buffered to acidic inputs, and has a moderate amount of hardness to ameliorate the toxicity of some metals. A number of metals occasionally have had concentrations which exceed BC approved or working water quality criteria to protect aquatic life. These metals included aluminum, iron, manganese, and lead. There are no known sources of metals to Deep Creek other than possibly stormwater runoff from Armstrong and alum which was used at the City of Armstrong for phosphorus removal. Maximum concentrations of ammonia, nitrite, and nitrate were all below criteria. Phosphorus concentrations were high enough to cause excessive algal growth if phosphorus is the limiting factor. Dissolved oxygen concentrations in Deep Creek were occasionally below criteria to protect aquatic life. Dissolved solids concentrations in Deep Creek can on occasion exceed water quality criteria to protect aesthetics of drinking water supplies.

Lower Vernon Creek is also considered to be well-buffered to acidic inputs, and to have moderate water hardness. Metals, which occasionally were at concentrations greater than the criteria, were aluminum, iron, and lead. The only known sources of metals to lower Vernon Creek are storm water runoff. Maximum concentrations of ammonia, nitrite, and nitrate were all below criteria. Phosphorus concentrations were high enough to cause excessive algal growths if phosphorus is the limiting factor. Dissolved oxygen concentrations infrequently were below criteria to protect aquatic life.

WATER QUALITY OBJECTIVES

Water quality objectives have no legal standing and would not be directly enforced. The objectives can be considered as policy guidelines for resource managers to protect water uses in the specified waterbodies. They will guide the evaluation of water quality, the issuing of permits, licenses, and orders and the management of the fisheries and of the Province's land base. They will also provide a reference against which the state of water quality in a particular waterbody can be checked, and serve to make decisions on whether to initiate basin-wide water quality studies.

Depending on the circumstances, water quality objectives may already be met in a waterbody, 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 waterbodies and for water quality characteristics which may be affected by man's activity now and in the foreseeable future.

Designated water uses for all three waterbodies are for the protection of aquatic life, wildlife, irrigation, livestock watering, and drinking water supplies.

Water quality objectives which are based on approved BC water quality criteria are proposed for microbiological indicators, turbidity, suspended solids, ammonia, nitrite, nitrate, pH and periphyton chlorophyll-a (to reflect the impacts from nutrients, especially phosphorus). The objectives are required to ensure that inputs from non-point source discharges and from the Armstrong and Vernon sewage treatment plants do not impair water uses. An objective is proposed for pH as a range of values. The upper value will control the formation of toxic quantities of ammonia. Dissolved oxygen levels proposed for the waterbodies are based on the Canadian Water Quality Guidelines, but are more restrictive.

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MONITORING RECOMMENDATIONS

WATER QUALITY OBJECTIVES AND MONITORING TABLES

To protect water uses in a waterbody, objectives specify a range of values for characteristics (variables) that may affect these uses. These values are maximum and/or minimum values that are not to be exceeded.

Some readers may be unfamiliar with terms such as: maximum concentration, 30-day average concentration, 90th percentile, and not applicable (NA). Maximum concentration means that a value for a specific variable should not be exceeded; 30-day average concentration means that a value should not be exceeded during a period of 30 days, when five or more samples are collected at approximately equal time intervals. The term 90th percentile indicates that 9 out of 10 values should be less a particular variable. Not applicable (NA) means that water uses are not threatened for that particular variable.