MBSS Site Summary for: AA-N-120-102-97


Located on BLACKHOLE CR in the Magothy River watershed, 8-digit code: 02131001.
This stream was visited in the spring on 3/26/1997 and again in the summer on 7/23/1997.

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 Poor - 1.7 / 5.0
Benthic IBI Poor - 1.9 / 5.0

Land Use

Land use can provide important information for determining stream health.
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Catchment area 407 acres A stream flowing through a densely forested area. An example of a forested stream.
Urban Land Use 0 %
Agricultural Land Use 21.4 %
Forested Land Use 78.4 %


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

Physical Stream Habitat
Instream Habitat 9/20 (Marginal)
Epifaunal Substrate 6/20 (Marginal)
Velocity/Depth Diversity 1/20 (Poor)
Pool Quality
Pool Extent = meters 		8/20 (Marginal)
Riffle Quality 0/20 (Poor)
Shading 90 %
Embeddedness 98 %
The embeddedness, a measure of silt on the stream bottom, was 98%. This is very high, and may adversely affect biotic communities.


Stream Water Quality:
Water temperature 19.1 ° C
Dissolved oxygen (DO) 0.7 mg/L
Dissolved oxygen levels measured in the stream were very low (0.7 mg/L). Many fishes and other aquatic animals cannot tolerate low levels of oxygen in the water.
pH (lab) 4
Conductivity 198 µmho/cm
Alkalinity
(acid neutralizing capacity) 		-108.8 µeq/L
Dissolved organic carbon (DOC) 4.6 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 1 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Eastern Mudminnow 667
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
American Bullfrog
Northern Green Frog
Southern Leopard Frog

Crayfish:
No crayfish noted.

Exotic Plants:
No exotic plants noted.
 

Benthic Macroinvertebrates:
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Genus/Family Common Name Count
Lumbriculidae Worm 6
Heterotrissocladius European Non-Biting Midge 4
Gammarus Amphipod 3
Cricotopus/Orthocladius Midge 3
Enchytraeidae Aquatic Worm 3
Trissopelopia Non-Biting Midges 3
Zavrelimyia Non-Biting Midges 2
Collembola Springtail 2
Hydroporus Water Beetle 2
Tribelos Non-Biting Midges 2
Apsectrotanypus Non-Biting Midges 2
Pseudorthocladius Non-Biting Midges 1
Rheocricotopus Non-Biting Midges 1
Chelifera Aquatic Dance Fly 1
Girardia Freshwater Flatworm 1
Caecidotea Isopod 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.