MBSS Site Summary for: CN-N-041-205-96


Located on GRAVELLY BR in the Upper Choptank watershed, 8-digit code: 02130404.
This stream was visited in the spring on 3/11/1996 and again in the summer on 8/22/1996.

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 - 3.3 / 5.0
Benthic IBI Good - 4.4 / 5.0

Land Use

Land use can provide important information for determining stream health.
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Catchment area 6,441 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 0 %
Agricultural Land Use 61.7 %
Forested Land Use 38.1 %


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

Physical Stream Habitat
Instream Habitat 18/20 (Optimal)
Epifaunal Substrate 16/20 (Optimal)
Velocity/Depth Diversity 15/20 (Suboptimal)
Pool Quality
Pool Extent = meters 		16/20 (Optimal)
Riffle Quality 16/20 (Optimal)
Shading 65 %
Embeddedness 100 %
The embeddedness, a measure of silt on the stream bottom, was 100%. This is very high, and may adversely affect biotic communities.
Several measures of instream habitat were considered 'Optimal' at this location.


Stream Water Quality:
Water temperature 20.8 ° C
Dissolved oxygen (DO) 9.5 mg/L
pH (lab) 6.38
Conductivity 143 µmho/cm
Alkalinity
(acid neutralizing capacity) 		34.9 µeq/L
Dissolved organic carbon (DOC) 6.9 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 10 fish species were collected.
Sensitive taxa: Green, Tolerant: Red, Intermediate: Gold.
Common name Count
Tessellated Darter 31
American Eel 27
Pirate Perch 22
Yellow Bullhead 13
Redbreast Sunfish 10
Margined Madtom 9
Pumpkinseed 5
Eastern Mudminnow 3
Bluegill 2
Creek Chubsucker 1
Biologists sampling fish communities.
Electrofishing to sample fish communities.

Amphibians and Reptiles:
American Bullfrog
Northern Green Frog
Pickerel 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
Prosimulium Black Fly 20
Isoperla Stripetail Stonefly 20
Stegopterna Black Fly 10
Orthocladius Non-Biting Midges 9
Cricotopus Non-Biting Midges 7
Conchapelopia Non-Biting Midges 6
Cheumatopsyche Net-Spinning Caddisfly 4
Ostrocerca Stonefly 4
Acerpenna Tiny Blue-Winged Olive Mayflies 4
Neophylax Caddisfly 4
Parametriocnemus Non-Biting Midges 3
Rheotanytarsus Non-Biting Midges 2
Eurylophella Mayfly 2
Sphaerium Fingernail Clam 2
Stenonema Flatheaded Mayfly 1
Pisidium Freshwater Pea (Pill) Clam 1
Clioperla Green-Winged Stonefly 1
Basiaeschna 1
Helius 1
Physa Air-Breathing Freshwater Snail 1
Gammarus Amphipod 1
Serratella Mayfly 1
Paraleptophlebia Blue Quill Mayfly 1
Optioservus Riffle Beetle 1
Cordulegaster Spiketail Dragonfly 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.