MBSS Site Summary for: AA-N-063-232-97


Located on DORSEY RUN in the Little Patuxent River watershed, 8-digit code: 02131105.
This stream was visited in the spring on 4/1/1997 and again in the summer on 7/21/1997.

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 - 3.7 / 5.0
Benthic IBI Fair - 3.3 / 5.0

Land Use

Land use can provide important information for determining stream health.
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Catchment area 750 acres A stream flowing through a densely forested area. An example of a forested stream.
Urban Land Use 9.8 %
Agricultural Land Use 14.2 %
Forested Land Use 72.5 %


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

Physical Stream Habitat
Instream Habitat 15/20 (Suboptimal)
Epifaunal Substrate 13/20 (Suboptimal)
Velocity/Depth Diversity 6/20 (Marginal)
Pool Quality
Pool Extent = meters 		16/20 (Optimal)
Riffle Quality 7/20 (Marginal)
Shading 85 %
Embeddedness 40 %


Stream Water Quality:
Water temperature 20.8 ° C
Dissolved oxygen (DO) 1.2 mg/L
Dissolved oxygen levels measured in the stream were very low (1.2 mg/L). Many fishes and other aquatic animals cannot tolerate low levels of oxygen in the water.
pH (lab) 6.72
Conductivity 8 µmho/cm
Alkalinity
(acid neutralizing capacity) 		232.9 µeq/L
Dissolved organic carbon (DOC) 5 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
Rosyside Dace 259
Blacknose Dace 36
Creek Chub 19
White Sucker 19
Tessellated Darter 14
Eastern Mudminnow 6
Fallfish 4
Redfin Pickerel 3
Common Shiner 2
Redbreast Sunfish 2
American Eel 1
Longnose Dace 1
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
American Bullfrog
Eastern American Toad
Eastern Box Turtle
Northern Green Frog
Northern Spring Peeper
Northern Two-Lined Salamander

Crayfish:
No crayfish noted.

Exotic Plants:
No exotic plants noted.
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Leuctra  Rolled-Winged Stonefly 14
Parametriocnemus Non-Biting Midges 14
Conchapelopia Non-Biting Midges 6
Stegopterna Black Fly 5
Rheocricotopus Non-Biting Midges 5
Amphinemura Spring Stonefly 5
Orthocladiinae A Non-Biting Midges 4
Pseudorthocladius Non-Biting Midges 3
Rheosmittia Non-Biting Midges 2
Polypedilum Non-Biting Midges 2
Cryptochironomus Non-Biting Midges 1
Eukiefferiella Non-Biting Midges 1
Cricotopus/Orthocladius Midge 1
Diplectrona Net-Spinning Caddisfly 1
Rheotanytarsus Non-Biting Midges 1
Thienemanniella Non-Biting Midges 1
Ironoquia Northern Caddisfly 1
Centroptilum Small Minnow Mayfly 1
Hemerodromia Tiny Fly 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.