| KEY
TO AQUATIC ECOLOGICAL SYSTEMS |
|||
| 2 |
Stream 1st-2nd order or <30 miles long | ||
| 2 |
Stream 3rd-5th order or 30 - 100 miles long | ||
| 2 |
River >5th order or >100 miles long | Medium Prairie River | |
| 2 |
River >5th order and >200 river miles long and a direct tributary to the Yellowstone or Missouri River (Little Missouri, Tongue, Bighorn and Powder Rivers) | ||
| 2
|
Yellowstone
River downstream from Billings or the Missouri River downstream from
Great Falls |
||
| Perennial
1st or 2nd order stream above 1000m elevation in the Wolf Mountains,
Powder River Basin or Missouri Breaks |
|||
| 3 |
Small (< 100m2 in area), low gradient intermittent pools separated
by long breaks of dry stream bed, typically lacks downstream connectivity
to a large mainstem river |
||
| .
|
|||
| 4 |
Stream
1st-2nd order or <30 miles long |
||
| 4 |
Stream 3rd-5th order or 30 - 100 miles long |
||
| 4 |
River >5th order or >100 miles long |
||
| 4 |
River >5th order and >200 miles long and a direct tributary
to the Missouri River (Milk or Marias Rivers) |
||
| 4 |
The
Missouri River downstream from Great Falls |
||
| .
|
|||
| 5 |
1st order, origin from Valley Floor groundwater output |
||
| 5 |
1st-2nd
order or <30 miles long |
||
| 5
|
3rd-4th
order or >30 and <60 miles long |
||
| 5 |
4th-5th order, >60 miles long and a direct tributary to the Yellowstone
or Missouri River |
||
| 6 |
Cool-cold water tributaries that originate in the foothills and flow
out to prairie rivers that are too warm to support coldwater fisheries |
||
| 6 |
Coldwater tributaries that flow to foothills and valley intermountain
transitional rivers that maintain coldwater fisheries |
||
| 7 |
1st
- 2nd order or <15 miles long |
||
| 7 |
3rd - 4th order or 15 - 60 miles long |
||
| 7 |
5th order or >60 river miles and a direct tributary of the Intermountain
Transitional River |
||
| 8 |
1st or 2nd order, elevation >2400m, hydrology driven by alpine
snowmelt |
||
| 8 |
1st order, elevation from 1500 to 2400m, hydrology fed by ground water
discharge |
||
| -- BROWSE AQUATIC ECOSYSTEM LIST AND MAPS -- | |||
| Montana State Library, 1515 East Sixth Ave., Helena, MT 59620-1800 • 406-444-5354• fax 406-444-0581 • email: mtnhp@mt.gov | |||
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