Set aside as a Natural Preserve, Northrup Canyon is a mixed deciduous and conifer forest, a granite crag rises from the middle of the forest. Talus slopes cover the sides of the canyon. Sagebrush grows on the well-drained outwash and moraines that fill this glaciated canyon. Named after one of the original homesteaders of the area, stage coaches and freight wagons used to wind through and up the south side of Northrup Canyon.
The Banks Lake Wildlife Area is located in the upper Grand Coulee of central Washington. It is an artificial impoundment built to store and supply irrigation water for the Columbia Basin Irrigation Project. Banks Lake is over 50 miles long and varies from one to three miles in width. It has about 91 miles of shoreline, most of which is ringed with basalt cliffs and talus slopes. The timing and magnitude of reservoir fluctuations impedes the development of wetland and riparian vegetation along the lake margin, and, therefore, limits fish and wildlife habitat.
There are 9,140 acres within the Sun Lakes Wildlife Area. Very little wetland vegetation exists in this unit. The uplands are mostly occupied by a stiff sage/Sandberg bluegrass community. Big sage/bluebunch wheatgrass occurs where there are pockets of soil. Bare rock is the most common feature of this unit. Many spectacular and interesting geological features exist.
The complex is dominated by a series of open water bodies of varying depths, from relatively deep Banks Lake to a series of relatively shallow and smaller lakes below Dry Falls Dam.
Northrup Canyon is included within the proposed IBA boundary to encompass with wintering bald eagles, which utilize the lakes as foraging areas.
Shallow soils and rocky outcrops characterize the dry upland portions of this unit. A shrub steppe community, dominated by sagebrush, perennial forbs, cheatgrass, Sandberg bluegrass, and bluebunch wheatgrass occurs on these areas. In areas with deeper soils and on talus slopes, woody shrubs are more common. Intermittently-flooded depressions with poor drainage and alkaline soils support greasewood, saltgrass, and Basin wild ryegrass. Willows and Russian olives grow on the fringes of some cattail and bulrush wetland areas. There are about 23 islands in Banks Lake. The southern islands are basalt outcroppings, while the northern ones are granite. The islands vary in size from less than one acre to several acres. Steamboat Rock, in the northern part of the lake, is the largest of several peninsulas. The top of Steamboat Rock is a Research Natural Area. Across the lake to the east is the Castle Rock Natural Area. Both of these areas exhibit some uncommon examples of undisturbed, northern Columbia Basin vegetation associations.