Conceptual Ecological Models

• File Number: 8461.100
• Description: Adaptive Management Workgroup
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 1/1/3000
• Author: PRRIP
• Title: Conceptual Ecological Models
• Water Supply Pro - Doc Type: Project Overview

shallow channels, resulting in increased potential whooping crane roosting
habitat, and increased whooping crane use.
4. Mechanical creation and maintenance methods of habitat will have more
direct benefit to the target species and be more cost effective than pulse flow
and sediment augmentation.
5. The clear/level/pulse management will 1) reduce channel narrowing, incision,
vegetation encroachment, and increase sediment availability, and 2) maintain
Program improvements in channel areas.
6. The clear/level/pulse management will result in increase the occurrence of
channel areas approximating the habitat characteristics desirable for whooping
cranes and will result in increased whooping crane use.
Learning Hypotheses
I. Sediment erosion, transport, and deposition processes are important in the
maintenance of open-view width and sandbar dimensions.
2. Islands gain elevation through deposition of sediment in vegetation. As
islands grow, channels are confined at lower flows and bed degrades.
3. Bed degradation is not occurring throughout the central Platte.
4. Vegetation encroachment into channels has reached equilibrium with flow
changes.
5. A comprehensive assessment of the central Platte River's form and processes
controlling the form are necessary precursors to implementation and
interpretation of the effects of any treatments intended to modify the river's
form.
Priority Biological Hypotheses
Pallid sturgeon
Learning Hypotheses
1. Past water related activities have reduced the quantity or rate of flow in the
lower Platte River during the months of February through July causing
negative impacts to pallid sturgeon.
2. Current habitat conditions on the lower Platte River do not adversely affect
the likelihood of survival and recovery of the pallid sturgeon because that
reach of river appears to retain several habitat characteristics preferred by the
species.
3. Further alterations of discharge patterns or channel features that modify those
characteristics will irreparably alter this habitat for pallid sturgeon use, loss of
Platte River habitat will result in a catastrophic reduction in the pallid surgeon
population.
4. Flows and sediment transport in the central Platte River are important in the
creation and maintenance of pallid sturgeon habitat in the lower Platte River.
5. Flows in the central Platte River are not important in the maintenance of pallid
sturgeon habitat in the lower Platte River.
6. Wild pallid sturgeon select areas on the lower Platte River for use based on
micro- and macro-habitat characteristics as described in ...