Water System Improvements Project Rathbun Regional Water Association (RRWA)
Centerville, IA
Rathbun Regional Water Association provides potable water for (9) nine
counties in southeastern Iowa and (4) four counties in northeastern
Missouri. Water demands are expected to increase from a current demand
of 7.5 mgd to between 13 and 16 mgd by the year 2035. RRWA has retained
the services of McClure Engineering Company to assist in planning,
design, and construction of additional supply and treatment capacity.
A “Plant Siting Report” was completed in September of 2006. A site
adjoining the existing water treatment plant south of Lake Rathbun was
selected for construction of a new treatment facility.
A “Preliminary Engineering Report” was prepared in
April of 2007. This engineering effort examined a new lake intake, raw
transmission mains, and upgrading an existing water treatment plant
and/or constructing a separate new plant. The report includes cost
estimates for all alternates and varying flow rates of those
alternatives.
A “Design Brief” report was prepared in November of
2007. This final design report detailed the concepts and design
parameters for a new caisson-type intake structure and a new
conventional, surface water treatment plant.
Final design efforts began in December of 2007. The
project was divided into 4 distinct parts. The first is the
construction of a new caisson-type intake structure, complete with
intake piping and screens, at the south edge of Lake Rathbun. The new
intake structure will have the capacity of 17.5 mgd. The second part is
the construction of dual 20-inch diameter raw water transmission mains
from the caisson to the new water treatment plant site, approximately
6,000 feet.
The third part is the design and construction of a
new conventional water treatment plant with an initial capacity of 6
mgd with expansion possible to 12 mgd. The treatment plant features
dual Super Pulsating clarifiers, Centrol variable declining rate
filters with carbon media, a clearwell and new high service pumps. The
fourth portion of the project is the caisson superstructure and pumping
facilities. 4 submersible turbine pumps will be able to provide up to
17.5 mgd of raw water to both the existing and new water treatment
plant.
The overall construction cost is expected to range
from 28 to 30 million dollars. Project financing will come from loans
through the State’s Revolving Fund and local funds. Additional funding
sources being explored include monies from USDA Rural Development and
new Stimulus funding.
