The U.S. Army Corps of Engineers, Louisville District, conducted
a pilot application of Navigation Predictive Analysis Technique
(NAVPAT), a model for assessing incremental environmental
effects of commercial navigation traffic on main channel Upper
Mississippi River Pool 13.
Upper Mississippi River Pool 13 was divided into units of
similar habitat. Seasonal changes in stage and discharge were
included. River reaches were described, including analysis of
banks, mapping of depths and substrate, and measurement of water
velocity. The needed economic data were developed from 1989
actual usage of Lock 13 (44 million tons). Two traffic
scenarios, 44 and 88 million tons, were developed for the Pool
13 application. Each tow was a unique vessel and reflected
seasonal traffic patterns. Thirteen species life stages of
fishes were used in the analysis. The species life-stage models
represent other species that share similar life requisites. The
NAVPAT biological models are similar to those in Habitat
Evaluation Procedures (HEP) or Instream Flow Incremental
Methodology (IFIM) models.
The results of the pilot application of NAVPAT indicate that
seven species life stages could be impacted by doubling existing
commercial navigation traffic. Substantial decreases in NAVPAT
units would occur with an increase of commercial navigation
traffic from 44 to 88 million tons for four species life stages,
with lesser decreases projected for three species life stages.
The remaining six life stages reflect little loss of NAVPAT
units.
