American River (Agiapuk River tributary) facts for kids

The American River is a waterway in the U.S. state of Alaska. It is found on the northwestern part of the Seward Peninsula. This river is the larger, eastern branch of the Agiapuk River.

The American River meets the Agiapuk River in a wide, gravelly area. For about 20 miles upstream, the American River flows through a wide, flat area called a flood plain. It also has a winding path. Many large streams, called tributaries, flow into it from the east. These tributaries also have wide flood plains near where they join the main river.

Important tributaries include Portage Creek, Budd Creek, and Igloo Creek. Smaller ones are Burke, Gold Run, Dome, and Camp creeks. People looking for gold, called prospectors, explored all these streams. Small boats can easily travel on the American River for several miles past Portage Creek. You can also reach this area from Teller. Gold was first found here in September 1901. Many streams in the area were known to have some gold.

Exploring the American River's Tributaries

The American River has several streams that flow into it. These are called tributaries. Each one has its own unique features.

Portage Creek

Above Portage Creek, the American River flows east for about 20 miles. The main rock at the river's start is limestone from the Port Clarence area. This limestone is mostly unchanged and doesn't have many minerals. Near where Portage Creek joins, the rock changes to a mix of limestone and mica-schist.

Portage Creek starts about 15 miles southwest of Shishmaref Inlet. It flows east for several miles through a canyon. This canyon is part of a plateau that slopes down to the inlet. Then, the creek turns south and flows through a deep valley for 10 miles. It then joins the American River. For the last half-mile before joining, Portage Creek has a wide flood plain. Here, the creek winds back and forth a lot. Along Portage Creek, the main rocks are limestone and mica-schist. Sometimes, there are also layers of graphitic schist.

Budd Creek

Budd Creek flows into the American River from the east. This is about 6 miles downstream from Portage Creek. Budd Creek is between 15 and 20 miles long. About 3 miles from its mouth, a large stream called Windy Creek joins it from the south. About 10 miles upstream, Budd Creek splits into two parts. These parts come from the north and south. Their direction is set by how the main rocks are layered.

The rocks along Budd Creek are made of crystalline limestone, mica-schist, and graphitic schist. These rocks usually run north to south. They can be tilted at different angles, from flat to very steep. Kugruk Mountain, a few miles east of where Budd Creek splits, is made of quartz-mica-schist. This rock has been pushed up into a fold.

Below where the creek splits, Budd Creek sometimes goes underground. This leaves its bed dry unless there's a lot of rain. After flowing underground for about 2 miles, the creek comes back up in several springs. This happens where a thick layer of limestone, sloping slightly downstream, crosses the creek's path.

Windy Creek

Windy Creek flows into Budd Creek from the south. This is about 5 miles from Budd Creek's mouth. Windy Creek is about 5 miles long. It flows mostly north, following the layers of the main rock. This rock is made of thin layers of limestone. Between these layers are beds of graphitic schist. These rocks can be seen along almost the entire length of the creek.

Near the start of Windy Creek, its bed has many large greenstone rocks. These rocks come from layers of greenstone that are found within the limestone near the creek's source. The valley of Windy Creek is wide and filled with gravel. Along the sides of the valley, away from the creek bed, the gravel goes up the slopes. This forms clear gravel benches. One bank of the creek shows 6 feet of muck (wet soil) on top of 6 feet of gravel.

Igloo Creek

Igloo Creek is also called Lewis Creek on some maps. It flows into the American River a few miles before the American River joins the Agiapuk. Like Budd Creek, Igloo Creek flows west across the layers of the main rock. The rocks here are similar to Budd Creek. They include limestone, mica-schist, and graphitic schist. There are also some greenstone layers that have changed a lot.

Like Budd Creek, Igloo Creek goes underground for about a mile. This probably happens when it crosses the same limestone layer that causes Budd Creek to sink. In its lower part, Igloo Creek winds over a wide flood plain. From this plain, the hills rise gently to a flat-topped upland area. Igloo Creek carries a lot of water, except where it goes underground over the limestone beds.