Download presentation
Presentation is loading. Please wait.
Published byLee Powell Modified over 9 years ago
1
Standard River Code & RM Stream Name New Station ID Location Description Date Scorer Lat/Long QHEI Header
3
Identify Two Predominant Substrate Types ◦ By Amount or Function Two boxes in case one type is only dominant type (e.g., bedrock) Lines after boxes for checking or estimating % of all substrate types present Pebble count procedure provides good training for assessment of substrate
4
Substrate Size Categories Boulder: > 10” Boulders as slabs: flat rather than round pieces Cobble: 2.5” to 10” Gravel: 1/12” to 2.5” (note wide range) Sand: gritty texture Silt: greasy texture, inorganic Muck: decayed organic material Detritus: leaves, sticks, wood Hardpan: usually clay, hard gummy surface
7
Substrate Diversity ◦ Number of substrate types More substrate types = more “niches” Many fish and macroinvertebrate species are associate with specific substrate types Substrate Origin ◦ Informational ◦ From where did the substrates originate? Bedrock, tills, alluvial sediments, colluvial sediments?
8
Substrate Origin Limestone: Often contains fossils, easily scratched with knife, usually bedrock or flat boulders and cobbles Tills: Sediments deposited by glaciers; particles often rounded. Can be carried into non- glaciated areas Wetlands: Usually organic muck and detritus Hardpan: Clay – smooth, usually slippery Sandstone: Contains rounded fragment of sand “cemented” together Rip/Rap: Artificial boulders Lacustrine: Old lake bed sediments Shale: “Claystone,” sedimentary rock made of silt/clay, soft and cleaves easily Coal Fines: Black fragments of coal, generally SE Ohio only
9
Wolman Pebble Count Zig-Zag Pebble Count Riffle Stability Index Others
12
Pervuasiveness of silt cover & embeddedness Smother habitats Reduce oxygen penetration Fines fill interstitial spaces
15
Sands, other fines cover larger substrates “Dunes” indicate high bedload Can often dig down to larger substrates
16
Import of fines > export Results in “aggradation of sediments in riffles and pools Symptom can be “spongy” deposits of sands and fine gravels that smother larger riffle particles
18
High Embeddedness: “Fish-eye View”
20
Substrate Embeddedness
22
Fish IBI
23
Affects overall community structure Decrease substrate quality leads to loss of sensitive species Decreasing substrate quality leads to increase in omnivores Decrease substrate quality leads to decrease in many sport fish species (e.g., smallmouth bass).
24
Substrate Score vs IBI
26
QHEI Substrate Score
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.