Objective

• 1) Identify if Species in Greatest Conservation Need are located at sand dredge reaches in the Kansas River.
  
• 2) Determine if fish communities differ at dredge and reference reaches in the Kansas River.
  
• 3) Identify if habitat is altered in sand dredge reaches compared to reference reaches.
  
• 4) Measure the extent, if any, of fragmentation of habitat of sand dredging in the Kansas River.
  

Overview

Sand and gravel are essential materials for construction, and high-quality material is often found in rivers and streams. However, instream dredging may have adverse physical effects by altering the instream habitat and fragmenting the natural river. These alterations include head cutting, streambed degradation, and channel widening. Not only can dredging alter physical habitat needed by native fishes, but can create a behavioral barrier for migrating fish by creation of deepwater, low velocity areas may inhibit upstream migrations of native fishes. In the Kansas River, sand dredging has resulted in bank erosion, riverbed degradation, and channel widening. Currently the US Army Corps has issued nine dredging permits through 2012 from near Topeka to Kansas City. In addition, dredging on the Missouri River from Rulo, NE to St Louis will not continue after 2009 unless an Environmental Impact Statement is developed. The scientific evidence on the ecological effects of instream mining are limited (Meador and Layer 1998), and therefore agencies evaluating these effects have little information on which to base their decisions. Of the 21 Tier I and II fish species in the Aquatic Eastern Large Rivers priority area, 19 have been historically collected in the Kansas River and six (32%) have been collected in reaches below Lawrence by KSU since 2006. At least three species in greatest conservation need have been located from limited sampling near dredging operations and additional sampling (more sites and seasons with additional sampling gears) may collect other Tier I and II species in these reaches. Our study will help identify the habitat needs for Tier 1 and II species that are collected in the Kansas River at reference reaches and sites altered by dredging. This information can be used to assure the key large river habitats are preserved and more complete data on the population status and distribution of Tier I sand II species are more complete.