Big Rock Branch, Blue River Watershed (LW09)
Big Rock Branch, Blue River Watershed (LW09)
Big Rock Branch (1213200)
2.05 Miles
6.13 - 8.18
Cool-Cold Headwater
2015
Good
 

Overview

Big Rock Branch is a Class II trout stream tributary to the Blue River. It has been recommended that 2.5 miles in Iowa County be upgraded to a Class I trout fishery and an exceptional resource water (ERW). The Iowa County portion of the stream has some natural reproduction of brook trout while the Grant County portion has some natural reproduction of brown trout. Big Spring Branch has been ranked as a high priority for nonpoint source pollution reduction. Grazing and large barnyards along the stream are thought to be a major contributing source of nonpoint pollution to the stream.

Date  2001

Author   Aquatic Biologist

Historical Description

From: Smith, Tom D., and Ball, Joseph R., Lake and Stream Classification Project. Surface Water Resources of Grant County, Department of Natural Resources, 1972. Surface Area = 2.1B acres, Length = 3.0 miles, Gradient = 33 ft./mile, Flow = 0.5 c.f.s.

It is one of the eight spring-fed trout streams flowing into the Blue River in northeastern Grant County. The stream begins near the Iowa and Grant County line and flows northwest entering the Blue River three miles east of Castle Rock. It flows through very picturesque country characterized by rock outcrops and giant boulders. Large boulder-strewn pools with narrow riffles are common. Brown, brook and rainbow trout are found throughout the stream with the best trout water being located in the lower reaches. It only receives a moderate amount of fishing pressure. Natural reproduction of both brown and brook trout is found in this stream. Forage species are also common. A floodwater detention structure is scheduled to be constructed about one mile above the mouth as part of the Blue River P.L. 566 Watershed Project. When completed this structure should aontrol rapid runoff and lessen the damage to stream habitat. Aquatic game assets are restricted to a few muskrats and mink. Upland game varieties common to Grant County are found in the lands surrounding the stream. Public access is only possible from one bridge crossing in the lower reaches. Three dwellings are found along the banks.

Date  1972

Author   Surface Water Inventory Of Wisconsin

Historical Description

Big Rock Branch - Location of mouth T6N R1E Section 4 -3, Surface Area = 0.3 acres, Length = 0.5 miles, Gradient = 47.5 feet per mile, Total alkalinity = 260.0 mg/l, Volume of flow = 0.3 cfs. Most of the stream is intermittent within Iowa County and so its length is short. Most of its streambanks are heavily eroded in Iowa County. The permanent stream starts from a good spring. There is a sizable forage fish population consisting of sculpins, creek chubs, brook sticklebacks, stoneroller minnows, redbelly dace and johny darters. Trout are found in its lower sections, in Grant County. There is no land along its banks in public ownership at the present time and the only access is from a town road crossing.

From: Piening, Ronald and Threinen, C.W., 1968. Lake and Stream Classification Project. Surface Water Resources of Iowa County, Wisconsin Department of Natural Resources, Madison, WI.

Date  1968

Author   Surface Water Inventory Of Wisconsin

Natural communities (stream and lake natural communities) represent model results that use predicted flow and temperature based on landscape features and related assumptions. Ranges of flow and temperature associated with specific aquatic life communities (fish, macroinvertebrates) help biologists identify appropriate resource management goals. Wisconsin Natural Communities.
This is the most recent date of monitoring data stored in SWIMS. Additional surveys for fish and habitat may be available subsequent to this date.
Trout Waters are represented by Class I, Class II or Class III waters. These classes have specific ecological characteristics and management actions associated with them. For more information regarding Trout Classifications, see the Fisheries Trout Class Webpages.
Wisconsin has designated many of the state's highest quality waters as Outstanding Resource Waters (ORWs) or Exceptional Resource Waters (ERWs). Waters designated as ORW or ERW are surface waters which provide outstanding recreational opportunities, support valuable fisheries and wildlife habitat, have good water quality, and are not significantly impacted by human activities. ORW and ERW status identifies waters that the State of Wisconsin has determined warrant additional protection from the effects of pollution. These designations are intended to meet federal Clean Water Act obligations requiring Wisconsin to adopt an 'antidegradation' policy that is designed to prevent any lowering of water quality - especially in those waters having significant ecological or cultural value.
A water is polluted or 'impaired' if it does not support full use by humans, wildlife, fish and other aquatic life and it is shown that one or more of the pollutant criteria are not met.
The use the water currently supports. This is not a designation or classification; it is based on the current condition of the water. Information in this column is not designed for, and should not be used for, regulatory purposes.
Waters that support fish and aquatic life communities (healthy biological communities).
The use that the investigator believes the water could achieve through managing "controllable" sources. Beaver dams, hydroelectric dams, low gradient streams, and naturally occurring low flows are generally not considered controllable. The attainable use may be the same as the current use or it may be higher.
Streams supporting a cold water sport fishery, or serving as a spawning area for salmonids and other cold water fish species through natural reproduction. Representative aquatic life communities, associated with these waters, generally require cold temperatures and concentrations of dissolved oxygen that remain above 6 mg/L. Since these waters are capable of supporting natural reproduction, a minimum dissolved oxygen concentration of 7 mg/L is required during times of active spawning and support of early life stages of newly-hatched fish.
This is the water classification legally recognized by NR102 and NR104, Wis. Adm. Code. The classification determines water quality criteria and effluent limits. Waters obtain designated uses through classification procedures.
Streams capable of supporting a cold water sport fishery, or serving as a spawning area for salmonids and other cold water fish species. Representative aquatic life communities, associated with these waters, generally require cold temperatures and concentrations of dissolved oxygen that remain above 6 mg/L. Since these waters are capable of supporting natural reproduction, a minimum dissolved oxygen concentration of 7 mg/L is required during times of active spawning and support of early life stages of newly-hatched fish.