Casadepaga River

Casadepaga River
Country	United States
State	Alaska
District	Nome Census Area
Source	Seward Peninsula
- elevation	1,662 ft (507 m)
- coordinates	64°49′30″N 164°39′12″W / 64.82500°N 164.65333°W / 64.82500; -164.65333
Mouth	Niukluk River
- location	31 miles (50 km) northeast of Solomon
- elevation	164 ft (50 m)
- coordinates	64°58′12″N 164°04′30″W / 64.97000°N 164.07500°W / 64.97000; -164.07500Coordinates: 64°58′12″N 164°04′30″W / 64.97000°N 164.07500°W / 64.97000; -164.07500
Length	32 mi (51 km)
Location of the mouth of the Casadepaga River in Alaska

Casadepaga River (also Koshotok and Koksuktapaga) is a waterway in the U.S. state of Alaska, near Nome. It is the largest southern branch of the Niukluk River. It has a length of about 30 miles (48 km) and a general northeasterly course.

The gradient of this river does not exceed 13–14 feet (4.0–4.3 m) to the mile. From its mouth to a point within 2 miles (3.2 km) of the head of its longest tributary, the whole fall is not more than 400 feet (120 m). The drainage area is large and the stream is navigable for small boats and canoes for a distance of about 15 miles (24 km). The upland in which the Casadepaga Valley is incised ranges in elevation from 800–1,800 feet (240–550 m). The bed rock of the whole basin consists of the limestones and schists of the Nome group, including many veins and stringers of quartz, some of which are known to be auriferous (gold-bearing). The river occupies a broad and deeply gravel-filled valley, in the floor of which the stream bed is trenched to a depth of 30–150 feet (9.1–45.7 m), leaving well-marked gravel terraces and benches through nearly the whole length. In the lower part of the valley, the stream has cut to bed rock through the gravel deposits in only a few places, but in the headwaters region the gravels overlie broad rock-cut lynches on both banks.

Dawson Gulch joins the river nearly opposite Big Four Creek, which is named after its first four prospectors. On the mica-schist bed rock, which was reached by test pit, flue gold is found associated with garnet. There are several gulches on the east side of the creek between Big Four and Dixon creeks. Massive gray crystalline limestone caps Mount Dixon, north of Dixon creek. Below the limestone is mica schist carrying small quartz veins. Dry Gulch is a small channel incised in the terrace of the main valley. An important consideration relative to the gold resources of the river is the fact that the gold of Dry Gulch and similar streams was not found on bed rock, but occurs in the gravels of the terrace and is usually concentrated on clay seams.

On the map accompanying the 1899 report of Alfred Hulse Brooks, this river is vaguely indicated and named the Koshotok; but on the map in the report for 1900 it is called the Koksuktapaga. This was eventually softened into Casadepaga by the United States Geographic Board. The word is undoubtedly of local origin, but its true meaning has not been determined. It is suggested, however, that the last part of it means "mouth of the river" and the first part "loon," so a free translation would be "the river with a loon at its mouth."