Blockhouse Creek, Little Platte River Watershed (GP03)
Blockhouse Creek, Little Platte River Watershed (GP03)
Blockhouse Creek (944500)
14.36 Miles
0 - 14.36
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 Headwater, Cool-Cold Mainstem, Cool-Warm Mainstem
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.
Grant, Lafayette
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.
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.
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.

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.
Streams capable of supporting a warm waterdependent sport fishery. Representative aquatic life communities associated with these waters generally require cool or warm temperatures and concentrations of dissolved oxygen that do not drop below 5 mg/L.
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.
Streams capable of supporting a warm waterdependent sport fishery. Representative aquatic life communities associated with these waters generally require cool or warm temperatures and concentrations of dissolved oxygen that do not drop below 5 mg/L.
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.
Default FAL
Fish and Aquatic Life - Default Waters do not have a specific use designation subcategory but are considered fishable, swimmable waters.


Blockhouse Creek is one of the major tributaries to the Little Platte River. It begins in western Lafayette County and flows 14 miles toward the southwest where it joins the Little Platte River north of Dickeyville. Recent surveys have shown the upper half of Blockhouse Creek is mainly a coolwater non-game fi shery, while the lower half also contains a decent smallmouth bass fi shery with an occasional brown trout or walleye present. There are fishery easements in the lower creek upstream of Snowden Branch. The Ozark minnow, a state threatened species, was also found in this stream.

Date  2011

Author  James Amrhein


Blockhouse Creek is a seepage and spring fed tributary to the Little Platte River south of Platteville. The stream flows through a scenic country valley characterized by wooded steep sided slopes. There is a unique natural area through which the stream flows in its central portion. Historically, the stream had a reproducing smallmouth bass fishery (Smith and Ball, 1971). The smallmouth bass population in the stream has not been recently evaluated. There is some public access along the stream. Non-point sources of pollution are affecting instream habitat. Some pollution intolerant species listed on Wisconsin’s threatened and endangered species list have been found in Blockhouse Creek.

Date  2001

Author   Aquatic Biologist

Historical Description

A seepage- and spring-fed stream beginning near the Grant and Lafayette County line and flowing southwest to enter the Little Platte River two miles north of Dickeyville. This stream flows through some very scenic, inaccessible country. Tufa Falls is a well-known scenic attraction located along a high limestone cliff in the central portion of the stream. This large, moss-covered, porous rock formation was formed as a deposit from springs trickling over this limestone cliff. A beautiful icicle formation can be seen hanging from the tufa during the winter months. A recreational site and a small lake were proposed to be built on the stream two miles below Tufa Falls in 1965, but nothing has been done up to this date. A variety of bottom materials, numerous pools, good bank and instream cover, and good water quality make Blockhouse Creek a good smallmouth bass stream. Naturally reproduced smallmouth are found throughout the stream. An abundant forage fish population also inhabits the stream. Snowden Branch, its major tributary, is also a good smallmouth bass stream entering from the east one mile above the mouth. Bank erosion is moderate to heavy on Blockhouse Creek. Muskrats, mink, and a few puddle ducks inhabit the floodplain. The upland game includes deer, raccoon, squirrels, and ruffed grouse. Nineteen acres of shrub swamp wetland adjoin the lower reaches of the stream. Five bridge crossings and the Little Platte River provide access. Six farm dwellings lie adjacent to the stream.

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 = 27.28 acres, Length = 12.5 miles, Gradient = 29 ft./mile, Flow = 10.9 c.f.s.

Date  1972

Author   Aquatic Biologist

Blockhouse Creek, Little Platte River Watershed (GP03) Fish and Aquatic LifeBlockhouse Creek, Little Platte River Watershed (GP03) RecreationBlockhouse Creek, Little Platte River Watershed (GP03) Fish Consumption

General Condition

Blockhouse Creek was assessed during the 2018 listing cycle; new biological (macroinvertebrate and fish Index of Biotic Integrity (IBI) scores) sample data were clearly below the 2018 WisCALM listing thresholds for the Fish and Aquatic Life use. This water was meeting this designated use and was not considered impaired.

Date  2017

Author  Ashley Beranek


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.



Control Streambank Erosion
The DNR should work closely with the Wisconsin Department of Transportation staff, Southwestern Wisconsin Regional Planning Commission, and with Grant and Lafayette County LCD staff on reviewing erosion control measures associated with the reconstruction of US Highway 151 to assure maximum protection of nearby streams.
Monitor Fish Community
Assess instream fisheries habitat in the Little Platte Watershed - Blockhouse Creek and Mounds Branch.
Monitor Targeted Area
The following streams were monitored to determine if the streams should be considered for addition to the state’s list of impaired waters due to adverse instream habitat impacts from non-point pollution sources as required by section 303(d) of the Federal Clean Water Act: Blockhouse Creek and Mounds Branch Blockhouse Creek and Mounds Branch Sections of these streams were done in 2009 and are not recommend for listing.

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 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

Monitoring Projects

Watershed Characteristics

Blockhouse Creek is located in the Little Platte River watershed which is 154.94 mi². Land use in the watershed is primarily agricultural (46.20%), grassland (38%) and a mix of forest (10.40%) and other uses (5.50%). This watershed has 389.19 stream miles, 19.99 lake acres and 585.06 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked High for runoff impacts on streams, Not Available 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

Blockhouse Creek is considered a Cool-Cold Headwater, Cool-Cold Mainstem, Cool-Warm Mainstem under the state's Natural Community Determinations.

Natural communities (stream and lake natural communities) represent model resultsand 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.