STUDY AREA

NOCA, located in the north-central portion of Washington State (Figure 3.1), is a rugged and heavily glaciated area in the northern Cascade Mountain Range. The park is 1274 km² and ranges from 330 m to 2700 m in elevation (Liss et al. 1995). Climatic and geologic conditions, soils, and vegetation are diverse. Annual precipitation, originating largely from warm moist winds from the Pacific Ocean, exceeds 100 cm at low elevations and over 350 cm at high elevations. The park area east of the hydrologic crest of the North Cascades Mountain Range receives less precipitation than does the west side. Extensive glacial systems exist because most of the precipitation is snow. Low-forest, high-forest, subalpine, and alpine zones are the main vegetation zones present (Lomnicky et al. 1989; Liss et al. 1995). Lakes in this study are classified based on the vegetation zone surrounding each lake (Table 3.1). The lakes are capped by ice and snow for many months each year. The open-water period typically occurs between mid-June to mid-July and early October, although some alpine lakes do not always become free of ice and snow each year.

Table 3.1. Lake acroynyms, elevations, areas, depths, and vegetation zones of NOCA study lakes. Vegetation zones: alpine (1); subalpine (2); high-forest (3); low-forest (4).