Environmental Impact Statement - radioactive monticello

Description of Site and Environment
freshwater mussels within the Upper Mississippi River have been adversely impacted by
activities such as collection for the pearl button and cultured pearl industries, siltation
(associated with agriculture, poor land management, and impoundments), pollution from
agriculture and industrial chemicals, establishment and maintenance of the navigation channel,
dams, loss of appropriate fish host species, and competition from exotic species, particularly
the non-native zebra mussel (Dreissena polymorpha) (USGS 1999; Weitzell et al. 2003).
The range of some mussel species has been expanding above St. Anthony Falls as fish hosts
for mussel glochidia (ectoparasitic larvae of native freshwater mussels) can now circumnavigate
the two navigation locks at this location (Kelner and Davis 2002). Approximately 13 mussel
species currently occur upstream of St. Anthony Falls (Siteman 2003). Only six species were
recently collected above Coon Rapids Dam: white heelsplitter (Lasmigona complanata), giant
floater (Pyganodon grandis), plain pocketbook (Lampsilis cardium), fatmucket (Lampsilis.
siliquoidea), black sandshell (Ligumia recta), and pink heelsplitter (Potamilus alatus) (Kelner
and Davis 2002). No information on mussel species within the immediate area of Monticello is
available.
The zebra mussel became established in the Upper Mississippi River by 1992 and has
continued to spread throughout the river system. Its increase causes a decline among many
native mussels, as it can out-compete native species for oxygen and food and is so prolific that
it can smother native mussel beds (FWS 2001). Until recently, populations of the zebra mussel
within the Mississippi River had not been observed above the Twin Cities area (St. Anthony .
Falls Lock and Dam) (MNDNR 2005). They were not observed between RM 854 and RM 848
(Pool 1) and were found to be sparse between RM 848 and RM 797 (pools 2 and 3) (Kelner and
Davis 2002). However, in October 2005, it was reported that zebra mussels had been found in
Rice Lake, an impoundment of the Mississippi River, in Brainerd, Crow Wing County,
Minnesota (MNDNR 2006). Brainerd is about 94 mi upstream of Monticello. The Asiatic clam
(Corbicula fluminea), another invasive mollusc species that can cause condenser tube clogging
problems, has been found at the Monitcello site (e.g., in the discharge canal), but was not
observed in the traveling screen forebays that were recently dredged (NMC 2006).
Few Federally or State-listed aquatic species are known to occur in the four counties in which
Monticello and the related transmission lines of concern occur (i.e., Wright, Sherburne,
Hennepin, and Anoka counties) (see Table 2-3). No Federally or State-listed fish species have
been collected from the Mississippi River near the Monticello site (Xcel Energy 2004). The
Higgins' eye pearlymussel (Lampsilis higginsii) is the only Federally listed aquatic species
reported from the four-county area (Hennepin County), and this species is both Federally and
State-listed as endangered (FWS 2005a,c). Two State-listed mussel species of special
concern (MNDNR 2005), the creek heelsplitter (Lasmigona compressa) and black sandshell,
have been reported downstream from the Monticello site within the Coon Rapids Pool of the
Mississippi River and within the Rum River in the. Hennepin and Anoka counties area (Kelner
and Davis 2002).
NUREG-1 437, Supplement 26 2-22 August 2006 1