Watershed Maps & Description

Watershed Maps & Description


Below are extracts from reports EBA Engineering Consultants(2000) and Alluvia Environmental Solutions (2004):


The following text is extracted from the EBA report:


2.0 WATERSHED CHARACTERISTICS

2.1 General Physiography

The Priest Lake watershed (1131 ha) is located up-slope from the community of Van Anda at the north end of Texada Island. Priest Lake flows north-east into Van Anda Creek, which flows into the Malaspina Strait. The small watershed has a low overall relief and is characterized by rolling topography. There are many small wetlands and lakes in the watershed, including Spectacle Lake and Kirk Lake.

2.2 Climate and Hydrology

The climate on Texada Island is characterized as warm and relatively dry in the summer and moist and mild in the winter with very little snow. Texada Island, specifically the northern half of the island, is generally drier than the mainland Sunshine Coast. Texada Island receives 957 mm of precipitation per year, while average annual precipitation recorded at the Powell River airport is 1233 mm. While some precipitation does fall as snow, the mild maritime climate, combined with basin size and physiography, prevents snow from remaining for long periods of time. Consequently, snow is unlikely to persist through the low flow period.

2.3 Geology, Geomorphology and Soils

Bedrock at the northern part of Texada Island is characteristically volcanic basalt and breccia overlain by massive calcareous and dolomitic limestone at the very north part of the Island. There are a number of active limestone quarries that extract the pure limestone. Bedrock exposures may also include shale, siltstone, sandstone, conglomerate and coal. These are relatively weak friable and fissile rocks that break down into surficial material that has significant component of fines in the matrix .
The lower slopes of the study area are covered by accumulations of till, glaciofluvial, or glaciolacustrine material. Surficial materials are typically medium-textured pure sand (Quadra Sand) with very little silt and clay deposited as outwash deposits overlain with till and related glaciomarine drift . Depths range from less than 0 .2 m to greater than 1 m.
Surficial material is generally covered with litter, fermentation, humus and pedalogic soil. The overlying organic layer is generally thin (< 6 cm) and easily disturbed or removed.
There are extensive areas of low-lying ground between and adjacent to lakes in the study area. Some of these areas are poorly drained and swampy and are likely underlain with clayey and silty lake bottom material. There are also ‘strings’ of bogs and small lakes, that form, depending upon the depth of the present day water table.

2.5 Fisheries and Wildlife Characteristics

2.5.1 Fisheries

A rare and unique species of stickleback, called the Vananda Limnetic Stickleback has been recorded in Emily Lake, Priest Lake, and Spectacle Lake. Another species of stickleback has been recorded in Paxton Lake, which is located to the southwest of the Priest Lake watershed.

2.5.2 Wildlife

The island is known to support a large population of black-tailed deer, as there are no natural predators to the deer (i.e. cougar or bear) on the island. There are raccoon and beaver, as well as freshwater turtle, garter snakes, frogs, and the alligator lizard. The Texada Island bird list shows approximately 200 resident or transient bird species. Species of interest include osprey, bald eagles, Great Blue heron, the Rufous Hummingbird, and Black Brant geese.

2.5.3 Significant Vegetation

The BC Conservation Data Center (CDC) maintains an inventory of known occurrences of rare species or natural plant communities. The CDC database represents information available at the time of the request and is updated or amended regularly. The CDC database lists a number of red- and blue-listed vascular plant species on Texada Island, although not necessarily within the watershed of interest for this study. These are summarized in Table 2.2 below and are shown in the map compiled by the CDC in Figure 2.1 .

Table 2.2 List of Red- and Blue-Listed Plant Species Recorded on Texada Island

Vascular Plant Species Provincial List Status*
Macoun’s Groundsel (Senecio macounii) Blue-listed
chaffweed (Anagallis minima) Blue-listed
least moonwort (Botrychium simplex) Blue-listed
green-sheathed sedge (Carexfeta) Blue-listed
western St. John’s wort (Hypericum scouleri nortoniae) Blue-listed
fleshy jaumea (Jaumea carnosa) Blue-listed
one-leaved malaxis (Malaxis brachypoda) Blue-listed
northern adder’s-tongue (Ophioglossum pusillum) Red-listed
california sword-fern (Polystichum califomicum) Red-listed
poison oak (Toxicodendron diversilobum) Blue-listed

Source: BC Conservation Data Centre (August, 2000)

* Provincial List Status :

  • Red-listed includes any indigenous species or sub-species considered to be Extirpated, Endangered, or Threatened in BC.
  • Blue-listed includes any indigenous species or sub-species considered to be Vulnerable in BC. This map shows the depths of Priest Lake (from the Alluvia report):
priest lake bathymetic map