MBSS Site Summary for: ROCK-201-B-2007

Site Photos

Field photo showing stream conditions at site ROCK-201-B-2007-1 (Opens in a new window) Field photo showing stream conditions at site ROCK-201-B-2007-2 (Opens in a new window)

Located on Rock Creek North Branch in the Rock Creek watershed, 8-digit code: 02140206.
This stream was visited in the spring on 4/10/2007 and again in the summer on 6/27/2007.

Index of Biotic Integrity (IBI) Results:

An Index of Biotic Integrity (IBI) is a scientific tool used to identify and classify stream health. An IBI associates anthropogenic influences on a stream or with biological condition in the stream, and is formulated using data developed from biosurveys.
Details on the development and application of MBSS IBIs are in this document.
Fish IBI Fair - 3.0 / 5.0
Benthic IBI Poor - 2.3 / 5.0

Land Use

Land use can provide important information for determining stream health.
(Hint: Screen readers will announce definitions; mouse users can hover over dotted text.)
Catchment area 4,231 acres Cows standing in a stream at a site with high agricultural land use. Cows survey the sampling procedure at this extreme example of a highly agriculturalized site.
Urban Land Use 30.6 %
Agricultural Land Use 42.5 %
Forested Land Use 26.3 %


Stream showing woody debris, logs, and rocky substrate.
An example of woody debris in a stream.

Physical Stream Habitat
Instream Habitat 10/20 (Marginal)
Epifaunal Substrate 5/20 (Poor)
Velocity/Depth Diversity 11/20 (Suboptimal)
Pool Quality
Pool Extent = 75 meters 		16/20 (Optimal)
Riffle Quality
Riffle Extent = 3 meters 		6/20 (Marginal)
Shading 90 %
Embeddedness 60 %
The embeddedness, a measure of silt on the stream bottom, was 60%. This is relatively high, and may exclude some biota.


Stream Water Quality:
Water temperature 23.3 ° C
Dissolved oxygen (DO) 5.4 mg/L
pH (lab) 7.81
Conductivity 151 µmho/cm
Alkalinity
(acid neutralizing capacity) 		569.4 µeq/L
Dissolved organic carbon (DOC) 1.1981 mg/L

Biological Stream Condition:

Surveys of the organisms living within a stream can give indications of stream health. Species richness, or the number of different species present, as well as indicator species (species whose presence, absence or abundance can serve as a measure of environmental conditions) are informative for stream health. 		Close-up of a mayfly indicator species.

Fish Survey Results:
The following 12 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
White Sucker 28
Bluntnose Minnow 14
Largemouth Bass 12
Tessellated Darter 9
Silverjaw Minnow 8
Spottail Shiner 8
Potomac Sculpin 7
Fallfish 6
Cutlip Minnow 4
Creek Chub 3
Green Sunfish 3
Longnose Dace 3
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
American Bullfrog
Eastern American Toad

Crayfish:
Orconectes
Orconectes virilis

Exotic Plants:
Garlic Mustard
Japanese Barberry
Japanese Stiltgrass
Mile-A-Minute
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Tribelos Non-Biting Midges 19
Hydrobaenus Midge 11
Tanytarsus Non-Biting Midges 10
Dubiraphia Riffle Beetle 9
Ablabesmyia Non-Biting Midge 9
Paratendipes European Non-Biting Midge 5
Orthocladius Non-Biting Midges 5
Tubificidae Aquatic Worm 4
Simulium Black Fly 3
Thienemannimyia group Non-Biting Midges 2
Centroptilum Small Minnow Mayfly 2
Menetus Air Breathing Freshwater Snail 2
Micropsectra Non-Biting Midges 2
Microtendipes Non-Biting Midges 2
Orthocladiinae Midge 2
Coenagrionidae Narrowwinged Damselfly 2
Argia Narrow-Winged Damselfly 2
Cryptochironomus Non-Biting Midges 1
Physa Air-Breathing Freshwater Snail 1
Naididae Aquatic Worm 1
Ceratopogonidae Biting Midge 1
Prostoma Freshwater Nemertean (Ribbon Worm) 1
Stenacron Mayfly 1
Nigronia Megaloptera (Dark Fishfly) 1
Macronychus Riffle Beetle 1
Ferrissia Small Air-Breathing Freshwater Limpets 1
Tvetenia Non-Biting Midges 1
Zavrelimyia Non-Biting Midges 1
Pisidiidae Pill Clam 1
Kick net sampling for macroinvertebrates.
Sampling with a kick net.

Information disclaimer: The information and data on this page is for guidance and general planning purposes only. It should not be used to make decisions on specific matters.