fia contract 6/10/1982MEMORANDUM
FIA CONTRACT H-4012
Salina, Saline County, Kansas
10 June 1982
Beginning at approximately 9:00 a.m. on Thursday, 10 June
1982, at the Bucher & Willis offices in Salina, a meeting was held
to discuss the progress and status of the Salina flood insurance
study with Maurice Bowersox - Wilson & Company, Dean Boyer - Salina
City Engineer, Don Hoff - Assistant Engineer, Keith Rawlings -
Salina City Planner,"Rvc5Ec-,+Assistant City Planner,
GHL, and JNS.
Mulberry Creek was the first stream. discussed. JNS indicated
that the gage analysis for the USGS gage, 'Mulberry Creek near
Salina, Ks.', would appear to reduce the Mulberry Creek - FPI dis-
charges by about 30 to 40 percent. This size reduction in discharges
would probably provide enough levee freeboard, so that the Mulberry
Creek levee could be accepted by FEMA. But we would not be sure
until new Mulberry Creek profiles have been run. (100 -year FPI Q:=
37,000 cfs, 100 -year gage analysis Q =22,400 cfs.)
Next, Dry Creek was discussed. JNS explained Dry Creek TR -20
model and new discharges. Again a decrease in discharge size from
the Dry Creek - FPI values. Still have levee freeboard problem at.
West State Street Road, and results are presently being reviewed
by the Kansas City District, Corps of Engineers. COE has not com-
mented on profile results as of this date.(100-year FPI Q at Dry
Creek confluence = 7400 cfs, 100 -year TR -20 Q = 6930 cfs; 100 -year
FPI Q at..I-135 = 7400 cfs, 100 -year TR -20 Q = 3930 cfs.) At Craw-
ford Street and at West State Street Road, the Dry Creek discharges
decrease due to flood waters going into flood plain storage. At
the Magnolia Road Ditch box culvert under I-135, all four frequency
(10-, 50-, 100-, and 500 -year) water surfaces submerge the top of
the box culvert. Thus restricting the flow of water out of Salina
via Magnolia Road Ditch. The present Dry Creek.x-sections from
Mulberry Creek upstream past Schilling Manor were field surveyed
in February 1982. The field surveyed x -sections replaced the FPI
x -sections previously used. (100 -year water surface elevation at
Magnolia Road was decreased about 2.5 feet by using the lower dis-
charges and field surveyed x -section when compared to the COE-FPI
Dry Creek profiles.) The timing of the TR -20 hydrograph peaks in
the I-135 to Magnolia Road area was discussed (runoff from the
airport peaks first, followed very closely by the main Dry Creek
peak, and Magnolia Road Ditch trying to start peaking at about
the same time. The Magnolia Road Ditch hydrograph.peak is 8 to 12
hours long. Thus Dry Creek water surfaces impede Magnolia Road
Ditch flows to Dry Creek).
Magnolia Road Ditch was discussed next. The Magnolia Road
Ditch profiles were computed with a normal depth start at the
confluence, and the 100 -year water surface elevations between
South Ninth Street and Edward Street along Magnolia Road Ditch
approximately matches the 100 -year water surface elevation on Dry
Creek at Magnolia Road. The Magnolia Road Ditch discharges were
divided at the sotth edge of Bonnie Ridge and at the intersection
of Magnolia Road, Belmont Boulevard, and the U.P.R.R. tracks. At
tl.se points flow w:ts diverted from Magnolia Rbad Ditch into the
city to the north and east.
"The Slough" was next discussed. The original TR -20 discharge
were calculated for "the Slough" drainage area only. Then part of
the flow diverted from Magnolia Road Ditch was added to "the Slough".
discharges. The 10 -year and 100 -year water surface profiles were
developed along "the Slough" from Prescott Avenue to Wayne Avenue.
It appears discharges could be changed with little change in -water
surfaces..(± 0.5 ft.).
The 100 -year flood plain delineation was reviewed in the area
from I-135 on the west to Ohio Street on the east and from Magnolia
Road on the north to the south edge of Bonnie Ridge on the south.
The flood insurance study 100 -year flood plain from I-135 to Edward
Street was delineated at elevation 1240.0 ft. NGVD (1929 adj). The
South Salina drainage study proposed a 100 -year ponding elevation
of 1238.0 ft. NGVD at the pond site north of Magnolia Road and west
of I-135. The difference in water surface elevation is due to the
difference between the natural conditions of the area (as studied
in FEMA flood insurance -study) and the proposed drainage plan
(modifications to drainage areas and flow paths made in the South
Salina drainage study.) Concerning natural conditions, it appears
the Salina flood insurance study and South Salina drainage study
agree.
The 1238 -ft. elevation was shown in yellow on the Salina drain-
age 'study, 2 -ft. contour maps, while the additional area flooded
by the 1240 -ft. elevation was shown in orange.
The 100 -year water surface along "the Slough" has been developed,
but the 100 -year flood plain delineation has not been completed
(the next step in the work). The area from Wayne Avenue on the
south to Prescott Avenue on the north and from South Ninth Street
on the west to Ohio Street on the east has been mapped to a 2 -foot
contour interval. This 2 -foot contour mapping will be used to
delineate the 100 -year flood plain along "the Slough". JNS also
briefly pointed out problem of.street depressions collecting water.
The meeting broke up about 10:00 a.m. 'The City was asked if
they wanted a copy of the stream profile information. The City
replied no.
JNS