STRATIFIED RANDOM  SAMPLING  OF  SUBMERSED  AQUATIC  VEGETATION  ON
POOL 13, UPPER MISSISSIPPI RIVER SYSTEM, FROM 1998 TO 1999

Theresa Blackburn.  
Mississippi Monitoring Station, Iowa Department of Natural Resources, 206 Rose 
Street, Bellevue, IA 52031. 

In 1998, the Long Term Resource Monitoring Program initiated a stratified random 
sampling protocol to monitor submersed aquatic vegetation (SAV) in the Upper 
Mississippi River System (UMRS).  The primary objective of the monitoring is to 
determine the status and trends of SAV within target pools of the UMRS.  During 
each summer in 1998 and 1999, SAV data were collected in Pool 13 at 550 sites 
randomly distributed within shallow aquatic areas (<=3 m in 1998 and <=2.5 m in 
1999).  The shallow aquatic areas were classified into 7 habitat strata including 
contiguous and isolated backwaters, main and side channel borders and the 
impounded area.  Data collected included both visual observation and rake samples. 
The data enable us to construct a profile of SAV in each habitat stratum and in the 
entire Pool 13.

Frequency of SAV remained about the same throughout Pool 13 in 1998 and 1999. 
Isolated backwaters contained the most SAV in both 1998 and 1999.  Fifteen species 
of SAV were encountered in Pool 13 in both 1998 and 1999 with thirteen species 
occurring in contiguous backwater strata in 1998 and thirteen species occurring in 
the impounded area in 1999.  Coontail (Ceratophyllum demersum) and sago 
pondweed (Potamogeton pectinatus) were the most frequently encountered and 
abundant species in both years in most strata.  Coontail was not sampled at main 
channel boarder sites in 1999.  Coontail and sago pondweed were distributed 
throughout the entire pool.  Eurasian milfoil (Myriophyllum spicatum), wild celery 
(Vallisneria americana) and water stargrass (Heteranthera dubia) were not found in 
backwater isolated strata and were distributed only in the lower half of the pool. 

Keywords:  submersed aquatic vegetation, Upper Mississippi River, trend analysis, 
stratified random sampling, Long Term Resource Monitoring Program
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