Big Rock Branch, Blue River Watershed (LW09)
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Big Rock Branch, Blue River Watershed (LW09)
Big Rock Branch (1213200)
2.91 Miles
0 - 2.91
Natural Community
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.
Cool-Cold Mainstem, Cool-Cold Headwater
Year Last Monitored
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.
2024
Unknown
 
Grant, Iowa
Trout Water 
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.
Yes
Outstanding or Exceptional 
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.
No
Impaired Water 
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.
No

Fish and Aquatic Life

Current Use
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.
Supported Aquatic Life
Waters that support fish and aquatic life communities (healthy biological communities).
Attainable Use
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.
Cold (Class II Trout)
Streams 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 through natural reproduction and selective propagation. 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.
Designated Use
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.
Cold
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.

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

Big Rock Branch, Blue River Watershed (LW09) Fish and Aquatic LifeBig Rock Branch, Blue River Watershed (LW09) RecreationBig Rock Branch, Blue River Watershed (LW09) Fish Consumption

Condition

Wisconsin has over 84,000 miles of streams, 15,000 lakes and milllions of acres of wetlands. Assessing the condition of this vast amount of water is challenging. The state's water monitoring program uses a media-based, cross-program approach to analyze water condition. An updated monitoring strategy (2015-2020) is now available. Compliance with Clean Water Act fishable, swimmable standards are located in the Executive Summary of Water Condition in 2018. See also the 'monitoring and projects' tab.

Reports

2020 Comprehensive WQ Assessments
2018 List of Healthy (Category 2) Waters
Comprehensive 2018 River/Stream Water Quality Assessments
Comprehensive 2016 Rivers Stream Assessments

Management Goals

Wisconsin's Water Quality Standards provide qualitative and quantitative goals for waters that are protective of Fishable, Swimmable conditions [Learn more]. Waters that do not meet water quality standards are considered impaired and restoration actions are planned and carried out until the water is once again fishable and swimmable

Management goals can include creation or implementation of a Total Maximum Daily Load analysis, a Nine Key Element Plan, or other restoration work, education and outreach and more. If specific recommendations exist for this water, they will be displayed below online.

Monitoring

Monitoring the condition of a river, stream, or lake includes gathering physical, chemical, biological, and habitat data. Comprehensive studies often gather all these parameters in great detail, while lighter assessment events will involve sampling physical, chemical and biological data such as macroinvertebrates. Aquatic macroinvertebrates and fish communities integrate watershed or catchment condition, providing great insight into overall ecosystem health. Chemical and habitat parameters tell researchers more about human induced problems including contaminated runoff, point source dischargers, or habitat issues that foster or limit the potential of aquatic communities to thrive in a given area. Wisconsin's Water Monitoring Strategy was recenty updated.

Grants and Management Projects

Project Name (Click for Details)Year Started
HARRY & LAURA NOHR CHAPTER OF TROUT UNLIMITE: Blue River/Big Rock Branch Project2013
Fish Propagation Actions2001

Monitoring Projects

WBICOfficial Waterbody NameStation IDStation NameEarliest Fieldwork DateLatest Fieldwork DateView StationView Data
1213200Big Rock Br10056329Big Rock Branch US Unnamed Trib (WBIC 5035933)5/7/20226/23/2024MapData
1213200Big Rock Br10007676Big Rock Branch at Spring Valley RdMapData
1213200Big Rock Br10022455Big Rock Branch At 1200m Upstream Spring Valley Rd (Senw2607n01w)1/1/20151/1/2015MapData
1213200Big Rock Br10022454Big Rock Branch Station 1 At 950m Upstream Of Spring Valley Rd (Senw2607n01w)1/1/20151/1/2015MapData
1213200Big Rock Br10015245Big Rock Branch General Fish1/1/20151/1/2015MapData

Watershed Characteristics

Big Rock Br is located in the Blue River watershed which is 216.19 mi². Land use in the watershed is primarily forest (41.60%), grassland (29.40%) and a mix of agricultural (20.80%) and other uses (8.20%). This watershed has 513.46 stream miles, 416.83 lake acres and 5,825.06 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked High for runoff impacts on streams, Not Ranked for runoff impacts on lakes and High for runoff impacts on groundwater and therefore has an overall rank of High. This value can be used in ranking the watershed or individual waterbodies for grant funding under state and county programs.However, all waters are affected by diffuse pollutant sources regardless of initial water quality. Applications for specific runoff projects under state or county grant programs may be pursued. For more information, go to surface water program grants.

Natural Community

Big Rock Branch is considered a Cool-Cold Mainstem, Cool-Cold Headwater under the state's Natural Community Determinations.

Natural communities (stream and lake natural communities) represent model results and DNR staff valiation processes that confirm or update predicted conditions based on flow and temperature modeling from historic and current landscape features and related variables. Predicated flow and temperatures for waters are associated predicated fish assemblages (communities). Biologists evaluate the model results against current survey data to determine if the modeled results are corect and whether biological indicators show water quaity degradation. This analysis is a core component of the state's resource management framework. Wisconsin's Riverine Natural Communities.

Cool (Cold-Transition) Mainstem streams are moderate-to-large but still wadeable perennial streams with cold to cool summer temperatures. Coldwater fishes are common to uncommon, transitional fishes are abundant to common, and warm water fishes are uncommon to absent. Headwater species are common to absent, mainstem species are abundant to common, and river species are common to absent.

Cool (Cold-Transition) Headwaters are small, usually perennial streams with cold to cool summer temperatures. Coldwater fishes are common to uncommon (<10 per 100 m), transitional fishes are abundant to common, and warm water fishes are uncommon to absent. Headwater species are abundant to common, mainstem species are common to absent, and river species are absent.

Fisheries & Habitat

Big Rock Branch in Grant County is a Class II and Class I trout stream tributary to the Blue River. 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. From: Ripp, Coreen, Koperski, Cindy and Folstad, Jason. 2002. The State of the Lower Wisconsin River Basin. PUBL WT-559-2002. Wisconsin Department of Natural Resources, Madison, WI.

Date  2002

Author  Cynthia Koperski

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