Ahjumawi Lava Springs State Park
|Ahjumawi Lava Springs State Park|
View east from the Ja-She Campground
|Location||Shasta County, California, USA|
|Nearest city||McArthur, California|
|Area||5,930 acres (2,400 ha)|
|Governing body||California Department of Parks and Recreation|
Ahjumawi Lava Springs State Park is a state park of California, USA, preserving a wilderness of freshwater springs and geologically recent lava flows. Unique in the California state park system, public access is by boat only. It is located in Shasta County, California. The state acquired the land from the Horr Ranch in 1975. There are 3 campgrounds — Horr Pond, Crystal Springs and Ja-She — each with three primitive campsites. Brilliant aqua bays and tree studded islets only a few yards long dot the shoreline. The size of the park is 4 miles (6.4 km) in length, 1 mile (1.6 km) or less wide and has over 13 miles (21 km) of shoreline. At the mouth of the springs, there are remains of Indian fish traps, low rock walls enclosing shallow water that were used to trap sucker and trout by the Ahjumawi. Of the park's 5,930 acres (2,400 ha), more than two-thirds of the area is covered by recent (two to five thousand years) lava flows including vast areas of jagged black basalt.
The park can be reached only by boat. There are no public roads to it and private motor vehicles are prohibited within. Visitors can launch into Big Lake at a Pacific Gas & Electric (PG&E) public boat launch known as Rat Farm.
John McArthur purchased land holdings in and around what is now known as McArthur Swamp in 1868. In 1924 PG&E bought the land  from the McArthur family to stop water diversions which were hampering the Pit 1 powerhouse downstream, and then leased it to John Masek who built and operated a muskrat farm around 1924. The muskrats were released in the 1930s and have become a concern due to possible environmental damage.
The launch ramp is unpaved and only suitable for shallow-draft boats. The launch site is reached from McArthur by turning north off State Route 299 on to Main Street, continuing past the Intermountain Fairgrounds, crossing over McArthur diversion canal and proceeding on a graded dirt road to a junction. Turn right on to Rat Farm road for 3 miles (4.8 km) to the launch and parking area.
The park brochure states "Where the waters come together" is a translation of the word Ahjumawi, which is said to be the self-describing word used by the band of Pit River- Achomawi Native Americans who inhabit the area. The Ahjumawi, also spelled (historically) Achomawi and Achumawi; and (more recently) Ajumawi, are one of nine bands comprising the Pit River tribe. The name translates to "River People." Sharon Ellmore, cultural information officer for the Pit River Tribe and the cultural representative for the Ahjumawi band gives a different translation: "My late grandmother, Edna Webster, was one of the elders and she used to say that in our language Ahjumawi means 'the river people, or the people who live by the river.'" 
The park and town of McArthur are in the Fall River Valley basin, a large valley bordered on the east and west by mountains and in the north by a volcanic plateau. A series of springs (1.2 billion gallons per day) discharge into the valley from the northern plateau which sustain the lakes and streams that merge in and around the park.
Some geologists believe the source of the springs is the Tule Lake and Klamath Lake basins, located 50 miles (80 km) north. The water then migrates underground through the porous basalt lava, resurfacing in the valley. The waters are Big Lake, Tule River, Ja-She Creek, Lava Creek, and Fall River. Together they form one of the largest systems of fresh water springs in the country. More recent work has shown that these spring waters are unrelated to Klamath Basin waters and instead are replenished by snow melt from Medicine Lake Volcano highlands area 
Preserved within the park are lava flows broken by great faults and deep cracks, lava tubes and craters. The freshwater springs flowing from the lava are prominent along the shoreline.
Oak, pine and juniper forests and slopes of rabbit brush and sagebrush are part of the great variety of vegetation in the area. Abundant wildlife populations are evident all seasons. A great variety of birds including, bald eagles, ospreys, and great blue herons nest or travel through the park. Herds of mule deer forage through much of the park.
Boaters, canoeists and hikers can explore the waterways, pools and lava flows. The park is also an excellent site for wildlife viewing, photography, picnics and overnight camping. Hiking trails vary in length from the 1.5-mile (2.4 km) Juniper Trail to the 5-mile (8.0 km) Lava Springs Trail. These paths show a variety of volcanic activity such as conic depressions, lava tubes and fields, as well as a spatter cone at the northern end of Spatter Cone Loop Trail. Visitors may be inspired by vistas of Mount Shasta, Mount Lassen and other nearby peaks.
Higher elevations tend to have much cooler temperatures and higher precipitation. Summer weather is usually hot and dry with lower elevation temperatures ranging from 85° - 100°+F and lows from 60° - 70°. Fall days are usually mild and warm, with cool nights. Winter is when most of the precipitation falls, averaging over 55 inches per year, much of it in the form of snow in the high elevations. Highs range from 40° - 60° and lows from 30° - 40° in the lower elevations.Spring weather is variable with many pleasant days. Elevation at McArthur is 3,311 feet (1,009 m) The park is administered from the nearby McArthur-Burney Falls Memorial State Park.
- The Intermountain News, Burney, Ca. Aug.14, 2002 p.3.
- Native Fish Traps Along the Shore of Ahjumawi Lava Springs State Park John W. Foster Senior State Archaeologist www.parks.ca.gov/pages/712/files/080202.pdf 
- Northeast California
- See USGS 7.5 Fall River Mills, Timbered Crater
- The Intermountain News, Burney, Ca. Aug.14, 2002 p.3
- Robert M. Norris & Robert W. Webb, Geology of California, John Wiley & Sons, 1976, p.86
- P. Charles Palmer, Marshall W. Gannett, Stephen R. Hinkle, Isotopic characterization of three groundwater recharge sources and inferences for selected aquifers in the upper Klamath Basin of Oregon and California, USA. Journal of Hydrology, 336, 17– 29
- Mariner, R. H.; Evans, W. C.; Huebner, M., Preliminary chemical and isotopic data for waters from springs and wells on and near Medicine Lake Volcano, Cascade Range, northern California. USGS Open-File Report: 98-2 http://pubs.usgs.gov/of/1998/0002/report.pdf