Memphis, MissouriWater Supply Study

Lake Show Me and Memphis Old Lake

Memphis Missouri is located in Scotland County, in northeast Missouri.

Memphis water supply comes from the city owned “Lake Show Me” and an older lake. Thelakes are located 2 miles southwest of Memphis in the North Fabius watershed.

Memphis Lake analysis consisted of using the NRCS's computer program called "RESOP".There are two lakes in series. Lake Show Me, the larger lake, is upstream of the old lake. Theold lake is not currently being used for water supply. This analysis consisted of evaluating thelake system in series with the current water demand coming only from the new lake. Both lakeswere also evaluated for their optimized yield.

In year 2000, Memphis used 153,276,495 gallons of water.

Following are considerations for data input to the "RESOP" program.

STO-AREA Elevation-Storage and Elevation-Area data were determined from June 19, 2001 survey made by USGS for the old lake and the new lake was surveyed on June 3, 2002.

Memphis Lake “Lake Show Me” Memphis Old Lake ------------------------------- ---------------------------- Elevation Area Storage Elevation Area Storage (feet) (acres) (ac-ft) (feet) (acres) (ac-ft) 728 1.91 1.01 706 0.81 0.58 730 6.38 9.16 708 2.26 3.65 732 11.70 27.13 710 8.42 12.48 734 17.30 55.95 712 19.94 40.68 736 23.22 96.36 714 27.81 89.59 738 30.40 149.42 715 30.09 118.59 740 38.47 218.33 716 32.04 149.63 742 46.46 303.00 718 40.49 219.51 744 57.07 406.47 720 50.12 309.39 746 68.04 531.36 721 57.50 364.87 748 79.01 678.14 750 91.64 848.42 Water Surface and Spillway 752 104.93 1044.60 Elevation on 6/19/01 = 718.0 754 119.12 1268.72 Top of Dam = 721.0 756 133.85 1521.70 758 149.19 1804.49 760 165.59 2119.03 762 181.47 2465.87 764 198.60 2845.44 766 214.18 3258.52 768 228.70 3701.31 769.8 244.93 4125.81 770 246.53 4174.95 772 262.08 4683.47 774 278.41 5223.82

Water Surface and SpillwayElevation on 6/3/02 = 769.8Emergency Spillway Elevation 774.0

LIMITS Lake Show Me Full Pool storage 4125.8 Ac.Ft. Minimum Pool storage 50 Ac.Ft. at approximate elevation 734. Old Lake Full Pool storage 219.5 Ac.Ft. Minimum Pool storage 10 Ac.Ft. at approximate elevation 710.

Starting storage was considered at full pool.

The drainage area of the upper lake is 2.66 square miles. The drainage area of the lower lake is 1.51 square miles. Total drainage area of the two lakes is 4.17 square miles.

GENERAL The adjustment factor of 0.76 to convert from pan evaporation to lake evaporation was applied prior to entering the data for the control word EVAP. As a result a factor of 100 is used.

The record period of drought is in the 1950's. Analysis began in January 1951 and ended December 1959.

SEEPAGELake Show Me

The reservoir seepage varied from 0 seepage near empty to a maximum of 2.0 inches per month at full pool. The seepage rate is a best estimate based on history of the reservoir, soil type, material of the core of the dam and compaction of the earth fill. The material in the dam is compacted earth of clayey soils.

When full the lake is about 40 feet deep, as a result the static pressure is fairly high and seepage is moderate. Old Lake The reservoir seepage varied from 0 seepage near empty to a maximum of 1.25 inch per month when at full pool. The material in the dam earth of clayey soils. This is an old dam and soil compaction is not as good as the Lake Show Me.

RAINFALL Rainfall data came from the Memphis, Mo. rain gage.

RUNOFF This is the runoff into the lake from its drainage area. Monthly runoff volumes in watershed inches were determined at the Middle Fabious stream gage, near Baring. The Gage is located approximately 8 miles south of Memphis.

EVAP. Pan evaporation at the Lakeside gaging station was used as a base because it has data for year around evaporation. All other stations only measure data

between April through November. Lakeside data was updated during these months with gage data from stations at Spickard, New Franklin, and Columbia. Depending on the latest data for the station nearest to Memphis.

DEMAND Year 2000 records show the daily usage at 0.4199 Million Gallons per Day.

OTHER Because there is no other inflow to the lake this control word was not used.

Memphis, MissouriWater Supply Study

Lake Show Me Storage Volume

725

735

745

755

765

775

785

0 1000 2000 3000 4000 5000 6000

Volume in Acre Feet

Elev

atio

n in

feet

Storage in Acre Feet

Spillway Elevation = 769.8 Feet

Figure 20.1.a

Memphis, Missouri Water Supply Study

Lake Show Me Surface Area

720

730

740

750

760

770

780

0 50 100 150 200 250 300

Surface Area in Acres

Elev

atio

n in

Fee

t

Spillway Elevation = 769.8

Figure 20.1.b

Surface Area in Acres

Memphis, MissouriWater Supply Study

Old City LakeStorage Volume

705

710

715

720

725

0 100 200 300 400

Volume in Acre Feet

Elev

atio

n in

Fee

t

Storage In acre feet

Spillway elevation = 718.0 Feet

Figure 20.1.c

Memphis, Missouri Water Supply Study

Old City Lake Surface Area

704

706

708

710

712

714

716

718

720

722

0 10 20 30 40 50 60 70

Surface Area in Acres

Elev

atio

n in

Fee

t

Spillway Elevation = 718.0 F t

Area in Acres

Figure 20.1.d

Memphis, MissouriWater Supply Study

Lake Show MeLake Storage

0

500

1000

1500

2000

2500

3000

3500

4000

4500

1951 1952 1953 1954 1955 1956 1957 1958 1959

Year

Stor

age

in A

cre

Feet Year 2000 Demand = 0.420 MGD

Optimum Demand = 0.78 MGD

Maximum Storage = 4125 Acre Feet

Minimum Available Storage = 50 A F t

Figure 20.2.a

Memphis, MissouriWater Supply Supply

Old Memphis LakeLake Storage

0

50

100

150

200

250

1951 1952 1953 1954 1955 1956 1957 1958 1959

Year

Stor

age

in A

cre

Feet

Optimum Demand = 94,600 gallons per day.

Maximum strorage = 220 Acre Feet

Lake is not currently being used for water supply

Figure 20.2.b

Memphis, MissouriWater Supply Study

Water Use

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

Year

Dem

and

in M

illio

n G

allo

ns p

er D

ay

Trend

Figure 20.3

Demand in year 2000 = 4.20 MGD

0 300 600 900 1,200 FEET

0 100 200 300 400 METERS

Elevation Area Volume(feet) (acres) (acre-ft)

728.0 1.9 1.0730.0 6.4 9.2732.0 11.7 27.1734.0 17.3 55.9736.0 23.2 96.4738.0 30.4 149.4740.0 38.5 218.3742.0 46.5 303.0744.0 57.1 406.5746.0 68.0 531.4748.0 79.0 678.1750.0 91.6 848.4752.0 104.9 1,044.6754.0 119.1 1,268.7756.0 133.9 1,521.7758.0 149.2 1,804.5760.0 165.6 2,119.0762.0 181.5 2,465.9764.0 198.6 2,845.4766.0 214.2 3,258.5768.0 228.7 3,701.3769.8 244.9 4,125.8770.0 246.5 4,175.0772.0 262.1 4,683.5774.0 278.4 5,223.8

MEMPHIS (NEW) LAKE

Figure 20. Bathymetric map and table of areas/volumes of the New Memphis Lake near Memphis, Missouri.

Table 20. Lake elevations and respectiveareas and volumes. Spillway elevation isapproximately 774 feet. Datum is sea level.

770

770

770

760

760

750

750

750740

740

730

750

Scotland County

LOCATION MAP

MISSOURI

EXPLANATION

BATHYMETRIC CONTOUR—Shows altitude of the reservoir bottom.Contour interval 2 feet. Datum is sea level.

WATER SURFACE—Shows approximate elevation of water surface,June 3, 2002 (actual is 769.8 feet, table 20). Datum is sea level.

U.S. GEOLOGICAL SURVEY REFERENCE MARKER—Chiseled squarelocated on northwest corner of spillway. Elevation 773.8 feet. Datum is sea level.

770

760

nrchensText BoxFigure 20.4.a

0 150 300 450 600 FEET

0 50 100 200 300 METERS

MEMPHIS (OLD)RESERVOIR

Figure 13. Bathymetric map and table of areas/volumes of the Old Memphis Reservoir near Memphis, Missouri.

Table 13. Lake elevations andrespective areas and volumes.Spillway elevation is 718.0 feet.Top of dam is approximately721.5 feet. Datum is sea level.

718

710

718

720

720

721

721

721

Elevation Area Volume(feet) (acres) (acre-ft)

706.0 0.8 0.6708.0 2.3 3.7710.0 8.4 12.5712.0 19.9 40.7714.0 27.8 89.6715.0 30.1 118.6716.0 32.0 149.6718.0 40.5 219.5720.0 50.1 309.4721.0 57.5 364.9

EXPLANATION

BATHYMETRIC CONTOUR—Shows altitude of the reservoir bottom.Contour interval 2 feet. Datum is sea level.

WATER SURFACE—Shows elevation of water surface, June 19, 2001(table 13). Datum is sea level.

U.S. GEOLOGICAL SURVEY REFERENCE MARKER—Chiseled squarelocated on northwest corner of spillway. Elevation 721.1 feet. Datum is sea level.

718

710

710

Scotland County

LOCATION MAP

MISSOURI

nrchensText BoxFigure 20.4.b.

200_ Memphis i&a.pdf201a Memphis Lake Storage.pdf201b Memphis Lake Area.pdf201c Memphis Old Lake Storage.pdf201d Memphis Old Lake Area.pdf202a RESOP Lake Show Me.pdf202b RESOP Memphis Old Lake.pdf203_ Historical water use.pdf204a memphisnew.pdfPage 1

204b memphisold.pdfPage 1