TABLE OF CONTENTS

• Figures
  • Figure 1. Location of Lakelse Lake
  • Figure 2. Foreshore Development and Landform Suitaboility for Septic Tank Renovation around Lakelse Lake
• Tables
  • Table 1. Provisional Water Quality Objectives for Lakelse Lake and Tributaries
  • Table 2. Recommended Water Quality Monitoring for Lakelse Lake and Tributaries
• Preface
• Introduction
• Hydrology
• Water Uses
• Waste Discharges
• Water Quality Assessment
• Provisional Water Quality Objectives
• Monitoring Recommendations

FIGURES

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

A detailed technical appendix was prepared and forms the basis for the results and conclusions presented in this report.

HYDROLOGY

The lake is oriented in a north-south direction (Figure 1). There are several inflowing streams, some of the more important being Williams and Schulbuckhand Creeks. The lake drains from the southwest, via the Lakelse River, which flows into the Skeena River.

WATER USE

The lake serves as an important recreational centre for the residents of the Terrace-Kitimat-Prince Rupert area. The most popular recreational uses in decreasing order of importance are swimming, picnicking, sunbathing, camping and fishing. In 1973, a total of 1 800 000 recreational activity days were spent at the lake. The majority occurred in June through September. The annual benefit to residents of the Terrace-Kitimat-Prince Rupert area was estimated in 1973 to be $6,700,000. Assuming a similar volume of use, the recreational value was estimated at $17 000 000 in 1984.

Cutthroat trout are the main catch of the lake's recreational fishery. Winter-run steelhead trout overwinter in Lakelse Lake prior to spawning downstream from the lake. Both the summer and winter-run steelhead fishery are important, but fishing is restricted to fly fishermen in the Lakelse River downstream from the lake.

The Lakelse watershed is also important for anadromous salmonids. A majority of the returning pink and Chinook adults spawn below Lakelse Lake, and their fry do not use the lake for rearing. The Coho spawn above and below the lake, and Coho fry will utilize the lake for up to two years. The sockeye exclusively use the tributaries of the lake for spawning and their fry utilize the lake for one year. The numbers of salmonids annually caught by the commercial fishery, which are attributable to the Lakelse watershed, average 1 100 000 pink, 300 Chinook and 25 000 Coho

In total, the Lakelse watershed represents 35 percent of the total Skeena River fishery for all species. In 1984 the value of this fishery was estimated to be $1 800 000.

WASTE WATER DISCHARGES

The suitability of the soils around Lakelse Lake for the renovation of septic effluent (Figure 2) was determined by their physical characteristics (permeability, depth of soil, texture) and their chemical characteristics (phosphorus absorption ability).

The majority of soils around Lakelse Lake are moderate to poor for the renovation of septic tank effluent. Only a small portion of the Lakelse Lake shoreline on the west shore near the outlet has soils considered good for the renovation of effluent. Approximately 250 houses are located within the watershed. The majority are located near the foreshore, on soils with moderate to poor sustainability. As a general guide, and in the absence of more detailed information, septic tank tile fields should be set back from the lake and inflow streams as follows: 35 m for soils with good sustainability, 90 m for soils with moderate sustainability, and 175 m for soils withpoor sustainability.

The main concern of logging within the Lakelse Lake watershed is the siltation of spawning and rearing streams. There has not been any data collection within the Lakelse Lake watershed to quantify the impact of logging. A total of 4 700 ha have been cut to date throughout the watershed over the past 30 years. An additional 2 900 ha of logging is proposed principally within the Williams and Hatchery Creek watersheds.

WATER QUALITY ASSESSMENT

Water quality data have been collected since 1974 by both the Federal and Provincial Governments. Maximum lake surface temperatures did not exceed 17 degrees Celcius, an optimal growing temperature for salmonids. Dissolved oxygen concentrations were typical of well flushed lakes. Summer concentrations did not drop below 50 percent saturation (6.5 mg/L) in the bottom waters.

Water clarity, measured by turbidity and Secchi disc, was relatively good during nonfreshet periods. Well flushed lakes typically have higher turbidity during freshet. The turbidity range for Lakelse Lake during freshet period was 1 to 2 NTU. High turbidity results were also recorded in November and December of 1974. High watershed runoff did not precede this particular period. Consequently, the high turbidities were probably the results of man's activity within the watershed and not due to flood conditions.

The Lakelse Lake area receives small amounts of acid precipitation generated from industrial sources. The aluminum smelter and to a lesser degree the pulp mills at Kitimat and Prince Rupert are the major sources of acid-generating air pollutants. The majority of rain samples collected at Terrace Airport were mildly acidic. A few highly acidic results have been measured during the summer months. Storm movements in the fall, winter, and spring are predominately from the north, i.e. from Terrace towards Kitimat. In the summer, storm movements are reversed causing more acidic rain in the Terrace area.

Lakelse is considered a soft water lake with a low to moderate sensitivity to acid rain. However, acid loading rates are not sufficiently high to pose a hazard to fisheries or drinking water supplies, and fluoride emissions should not pose an acidification problem to the lake or inflow streams.

Nitrogen and phosphorus are the critical micronutrients in freshwaters. Phosphorus was determined to be the nutrient limiting phytoplanktonic growth and hence biological productivity in Lakelse Lake. Total phosphorus concentrations were typically below 0.010 mg/L. The 1983 and 1984 spring overturn phosphorus concentrations were 0.008 to 0.010 mg/L.

Abnormally high total phosphorus concentrations were observed from November 1974 through May 1975. Maximum concentrations reached 0.066 mg/L in May. Subsequent flushing reduced the concentrations below 0.010 mg/L, a level typical for the lake.

Two observations may explain the high phosphorus results recorded in 1974-75. One was the association of the phosphorus peak with high turbidity results. The other was a small forest fire (1 ha) at the south end of the lake in August on which 2.4 tonnes of fire retardant containing some phosphate was used. Leaching of the retardant and other materials from the burnt area is thought to be responsible for the elevated phosphorus and turbidity results.

The algal standing crop of a lake is usually estimated by chlorophyll-a. Only one year of chlorophyll a data is available. The mean summer chlorophyll-a for Lakelse Lake was 0.0025 mg/L in 1974. The concentration of chlorophyll-a is determined by the phosphorus concentration. Increased phosphorus loading will result in increased chlorophyll a (manifested by algal blooms) which can affect water quality. The chlorophyll a levels in 1974 were ideal for supporting water contact recreation and a cold water fishery.

Lakelse Lake is considered to be oligotrophic because of its low phosphorus concentrations, low oxygen depletion rates of the bottom waters, and low chlorophyll-a results. These attributes, in association with the lake's good water clarity, collectively determine the recreational and fisheries importance of the lake.

WATER QUALITY OBJECTIVES

Provisional water quality objectives were established to protect the most sensitive water uses of Lakelse Lake and 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 uses and limnological characteristics. 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. This is due to the natural variability of the aquatic environment, and the difficulty of attributing contamination that exceeds the objective to particular sources for legal purposes, and thus 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 waterbodies and for water quality characteristics which may be affected by man's activity, now and in the foreseeable future.

The designated water uses to be protected in Lakelse Lake are:

• aquatic life (anadromous fish rearing habitat, recreational freshwater fishery)
• primary contact recreation
• drinking water supply

• aquatic life (salmonid spawning and rearing-anadromous and nonanadromous species)
• drinking and irrigation water supplies
• primary contact recreation in the Lakelse Lake hotsprings.

The provisional water quality objective for fecal coliform bacteria near or in water intakes is: not more than 10 percent of at least 5 samples from each site in any 30-day period, should not have a fecal coliform density greater than 10/100 mL (i.e., the 90th percentile should be less than or equal to 10/100 ml).

The provisional objective for fecal coliform bacteria samples taken at public beaches during the summer months is: a maximum running log mean of 200/100 ml, calculated from at least 5 weekly samples taken during the recreation season, and not more than 10 percent of samples during any 30-day period to exceed 400/100 ml

Although no bacterial data are available, there seems to be no reason to believe that these objectives are not presently being met. Monitoring will be required to check the situation.

Nuisance algal growth in lakes, as measured for example by chlorophyll-a is usually the result of excessive phosphorus in a lake. Algae can cause taste and odours in drinking water, aesthetic problems, poor water clarity and pypolimnetic oxygen depletion which results in loss of fisheries habitat and possible winter or summer kill situation.

Water quality objectives are proposed for the mean summer concentration of chlorophyll a and total phosphorus. These objectives are: average chlorophyll-a 0.003 mg/L and average total phosphorus 0.010 mg/L, both applicable over the spring and summer period.

The averages should be calculated from at least monthly samples taken in the period May to August. For the measurement of total phosphorus, 3 discrete samples should be taken each month at the deepest part of the late at 0.5, 6 and 30 m depths. Samples for measurements of chlorophyll a can be taken at the same time and site, and should consist of a composite of samples taken at depths of 0, 2, 4 and 6 m, or a composite sample from 0 to 6 m using a tygon tube.

An objective is also proposed for the dissolved oxygen content of the hypolimnion in order to maintain the cold water fishery and zooplankton habitat of the lake. The dissolved oxygen content should not drop below 6.0 mg/L, at any point greater than 5 m above the sediment-water interface.

A turbidity objective is proposed for Lakelse Lake, the inflow streams used for domestic water supplies, and streams important for salmonid spawning in areas subject to logging. For steams with both domestic water supplies and salmonid spawning, the objective for domestic water supplies should apply.

The provisional turbidity objective for the lake and the inflow streams with domestic water supplies is an average of 1 NTU, and a maximum of 5 NTU. The objective is set to ensure that the water quality is suitable for domestic water supply (the most sensitive use) with no water treatment in addition to disinfection (i.e., no removal of turbidity or suspended residues is required). Because the freshet values are variable from year to year, and the results can exceed the 5 NTU objective, no turbidity objective is proposed for domestic water supplies during freshet. The turbidity objectives should apply to any discrete sample (surface or bottom) collected anywhere during non-freshet periods.

The turbidity objective for spawning streams is as follows: the induced turbidity should not exceed 5 NTU when background turbidity is less than or equal to 50 NTU, nor should the induced turbidity be more than 10% of background when background is greater than 50 NTU.

WATER QUALITY MONITORING

A summary of recommended water quality monitoring is given in Table 2. Monitoring is required to determine whether provisional water quality objectives are being met, and to provide ambient data to fill important data gaps. The amount of monitoring that can be done will depend on project priorities and availability of funds.

TABLES