Section 8 - Wastewater Storage Pond Design Colorado CNMP Workshop Wastewater Storage Pond Design Prepared by J.E. Andrews, PE, NRCS - Lakewood, CO

Colorado CNMP WorkshopColorado CNMP WorkshopSection 8 - Wastewater Storage Pond Section 8 - Wastewater Storage Pond DesignDesign

Wastewater Storage Pond Design

Prepared by J.E. Andrews, PE, NRCS - Lakewood, CO


Workshop Objectives

• Assemble some basic design data

• Estimate pond size required

• Develop a preliminary cost estimate


Consult with a knowledgeable Engineer to:

• Consider other options and alternatives• Evaluate pond site location(s) & lining requirements• Analyze technical requirements for

• storage period and pump needs• solids trap and snow removal• hydrologic & waste loading factors• need for treatment

• Design inlet, outlet & other related facilities• Prepare construction drawings & specs• Perform construction inspection


Location Site Options and Constraints Plans and Options for Future Expansion Soil Options and Constraints (clay borrow or liner) Surface or Groundwater Concerns and Constraints

Volume - needs to facilitate the utilization plan How will the liquids & sludge be removed and used? How often will (or can) the pond be emptied?

What is your concern level for odor control? What is your concern level for nutrient conservation? Features (shape, depth, side slope, inlet/outlet type, etc.) Operation & Maintenance Options and Requirements THINK SAFETY, SAFETY, SAFETY !!!

Design Considerations


Cross Section of a W aste Storage Pond

freeboard - 2 ft. min.

Start Pumping Level

Inside slope 3:1

Outside Slope3:1 or flatter

Seepage ControlLiner for

Waste Storagemanure, waste water,waste feed & bedding

accumulated solids

Normal Contaminated Runoff+ Precipitation - Evaporation On Pond Surface

25 year Storm Runoff

Working Storage

Top Width - 8' to 16'

Overflow Pipe or Spillway(when needed)


Information Needed for Estimating Pond Volume

• Storage Period• Size of Runoff Producing Areas

• Roofs, Paved Lots & Unpaved Lots• Areas for future expansion• Other Areas

• Climate Data for site location (including evaporation)• Volume of manure, wastewater & other by products

to be stored in the pond.• Worksheet #8 &Tables 8a, 8b & 8c


Example - Frank’s Dairy

• Located near Fort Morgan, Colorado

• Pond effluent can be applied May through September

• 5 acres of earthen feedlot & solid manure stacking area

• 2,000 sq. ft. concrete surfaced holding area

• 1,000 sq. ft. of roofs that drain across the concrete lot

• 2,000 gal. wastewater per day from the milking center

• Manure & other solids are kept out of the pond

• No plans for expansion at this site


Step 1 - Get Climate Data

Table 8a. COLORADO CLIMATE DATA FOR WASTE MANAGEMENT SYSTEM DESIGN

Runoff as % of Annual Rainfall3

Average Annual Annual FWS Paved Feedlot Earth Feedlot 25 yr - 24 hr

Precipitation1 Evaporation2 CN= 97 CN=90 Precipitaion4

County Climate Station (inches) (inches) (% of annual) (% of annual) (inches)

Montrose Cimmaron 3S 13.1 40 30% 10% 2.0Montrose Uravan 12.9 45 30% 10% 2.2Morgan Fort Morgan 12.7 48 43% 15% 3.4Morgan Wiggins 7SW 16.1 47 43% 15% 3.4Otero La Junta 15.7 55 45% 16% 4.0Otero Rocky Ford 2SE 11.7 54 45% 16% 4.0

@ Fort Morgan Climate Station

Annual Rainfall = 12.7” 43% runs off paved areas 15% runs off earthen feedlots

25yr-24hr Rainfall = 3.4”

Average Lake Evaporation = 48”


Worksheet 8. Waste Storage Pond Volume Determination

Facility Name: Frank's Dairy Location: Fort Morgan, CO

Prepared by: JEA date: Dec-00 Checked by:

Runoff Volume Computations

Average Annual Rainfall: 12.7 inches 25 year-24 hour Rainfall: 3.4 inches

Roofed Area (CN = 100) ( + ) x / 12 =Runoff Annual 25yr-24hr Roof Area Runoff Volume

Rainfall Rainfall (sq. ft.) (cubic feet)

Paved Area (CN = 97) ( + ) x / 12 =Runoff Annual 25yr-24hr Area Runoff Volume

Annual Runoff %: 43 Runoff Runoff (sq. ft.) (cubic feet)

Earthen Area (CN = 90 ) ( + ) x x 3,630 =

Runoff Annual 25yr-24hr Area Runoff Volume

Annual Runoff %: 15 Runoff Runoff (acres) (cubic feet)

Design Runoff Volume =(cubic feet)


Step 2 - Calculate Roof Runoff Volume


Facility Name: Frank's Dairy Location: Fort Morgan




Roofed Area (CN = 100) ( 12.7 + 3.4 ) x 1,000 / 12 = 1,342

Runoff Annual 25yr-24hr Roof Area Runoff Volume



Step 3 - Calculate Paved Area Runoff Volume


Facility Name: Frank's Dairy Location: Fort Morgan




Paved Area (CN = 97) ( 5.5 * + 3.06 **) x 2,000 / 12 = 1,420



* Annual Runoff = Annual Runoff % x Annual Rainfall 100

** Find 25yr-24hr runoff from 3.4” rain in Table 8b.


Runoff for Paved Surface Feedlots, Curve Number: 97tenths\

Inches 0.0 1.0 2.0 3.0 4.0 5.0 6.0

0 0.02 0.71 1.67 2.66 3.65 4.65 5.64

0.1 0.00 0.80 1.77 2.76 3.75 4.75 5.74

0.2 0.04 0.89 1.87 2.86 3.85 4.85 5.84

0.3 0.10 0.99 1.97 2.96 3.95 4.95 5.94

0.4 0.18 1.09 2.06 3.06 4.05 5.05 6.04

0.5 0.26 1.18 2.16 3.15 4.15 5.15 6.14

0.6 0.34 1.28 2.26 3.25 4.25 5.25 6.24

0.7 0.43 1.38 2.36 3.35 4.35 5.34 6.34

0.8 0.52 1.48 2.46 3.45 4.45 5.44 6.44

0.9 0.61 1.57 2.56 3.55 4.55 5.54 6.54

Finding runoff depth from a 3.4” rain on a concrete feedlot using Table 8b.


Step 4 - Calculate Earthen Area Runoff Volume

* Annual Runoff = Annual Runoff % x Annual Rainfall 100

** Find 25yr-24hr runoff from 3.4” rain in Table 8b.



Prepared by: jea date: Dec-00 Checked by:



Earthen Area (CN = 90 ) ( 1.9 * + 2.36 **) x 5.00 x 3,630 = 77,359




Finding runoff depth from a 3.4” rain on a earth surfaced feedlot using Table 8b.

(include areas outside the feedlot too)

Runoff for Earth Surfaced Feedlots, Curve Number: 90tenths\

Inches 0.0 1.0 2.0 3.0 4.0 5.0 6.0

0 0.06 0.32 1.09 1.98 2.92 3.88 4.85

0.1 0.02 0.39 1.18 2.08 3.01 3.97 4.94

0.2 0.00 0.46 1.27 2.17 3.11 4.07 5.04

0.3 0.01 0.53 1.35 2.26 3.20 4.17 5.14

0.4 0.02 0.61 1.44 2.35 3.30 4.26 5.24

0.5 0.06 0.68 1.53 2.45 3.40 4.36 5.33

0.6 0.10 0.76 1.62 2.54 3.49 4.46 5.43

0.7 0.14 0.84 1.71 2.64 3.59 4.55 5.53

0.8 0.20 0.93 1.80 2.73 3.68 4.65 5.63

0.9 0.26 1.01 1.89 2.82 3.78 4.75 5.73


Step 5 - Total Runoff Volumes






Roofed Area (CN = 100) ( 12.7 + 3.4 ) x 1,000 / 12 = 1,342



Paved Area (CN = 97) ( 5.5 + 3.06 ) x 2,000 / 12 = 1,420



Earthen Area (CN = 90 ) ( 1.9 + 2.36 ) x 5.00 x 3,630 = 77,359



Design Runoff Volume = 80,120(cubic feet)


Step 6 - Calculate Design Volume

* Process Wastewater Volume = 2,000 gal/day x 365 days/year / 7.5gal/cu. ft. = 97,333 cu. ft.

Storage Volume Computations

Design Runoff Volume, in cubic feet:(from calculations above)

Manure Solids Volume, in cubic feet:(Multiply tons/year by 50 cu. ft./ton)

Other Solids Volume, in cubic feet:

Liquid Manure Volume, in cubic feet:(Divide gal/year by 7.5 gal/cu. ft.)

Process Wastewater Volume, in cubic feet:(Divide gal/year by 7.5 gal/cu. ft.)

Total Volume Required, in cubic feet:


Step 7 - Choose Pond Dimensions

• Choose a depth between 6’ & 12’• As deep as possible within site limits• Pond bottom should be 4’ above the water table

• From Table 8c, select a length & width, such that:

• Fits available space• Selected volume is greater than design volume


Use Table 8c - for a given depth choose a width & length that results in a volume greater than 177,453 cu ft.

Table 8c. Volume of Retangular Ponds for given width, length & depth

8 Foot Depth T O P L E N G T H, F T. 3 : 1 Inside Slope

60 75 100 125 150 175 200 225 250 275

60 11,904 16,224 23,424 30,624 37,824 45,024 52,224 59,424 66,624 73,824

T. 75 16,224 22,344 32,544 42,744 52,944 63,144 73,344 83,544 93,744 103,944

F 100 23,424 32,544 47,744 62,944 78,144 93,344 108,544 123,744 138,944 154,144

, 125 30,624 42,744 62,944 83,144 103,344 123,544 143,744 163,944 184,144 204,344

H 150 37,824 52,944 78,144 103,344 128,544 153,744 178,944 204,144 229,344 254,544

T 175 45,024 63,144 93,344 123,544 153,744 183,944 214,144 244,344 274,544 304,744

D 200 52,224 73,344 108,544 143,744 178,944 214,144 249,344 284,544 319,744 354,944

I 225 59,424 83,544 123,744 163,944 204,144 244,344 284,544 324,744 364,944 405,144

W 250 66,624 93,744 138,944 184,144 229,344 274,544 319,744 364,944 410,144 455,344

275 73,824 103,944 154,144 204,344 254,544 304,744 354,944 405,144 455,344 505,544

P 300 81,024 114,144 169,344 224,544 279,744 334,944 390,144 445,344 500,544 555,744

O 350 95,424 134,544 199,744 264,944 330,144 395,344 460,544 525,744 590,944 656,144

T 400 109,824 154,944 230,144 305,344 380,544 455,744 530,944 606,144 681,344 756,544

500 138,624 195,744 290,944 386,144 481,344 576,544 671,744 766,944 862,144 957,344

Assume an 8 foot depth for Frank’s Dairy


Waste Storage Pond Design Volume: 177,453(cubic feet)

Approximate Design Dimensions Depth: 8 Width: 150 Length: 200(select dimensions from Table 8c that result in a pond volume equal or greater than the design volume)

Volume Selected: 178,944(cubic feet)

Step 8 - Estimate Construction Cost

Volume Selected x $0.10 per cu. ft. ~ Cost

178,944 x $0.10 = $17,894 (round to nearest $1,000)

Estimated Cost ~ $18,000


Worksheet 8 should now be complete for your operation.






Roofed Area (CN = 100) ( 12.7 + 3.4 ) x 1,000 / 12 = 1,342



Paved Area (CN = 97) ( 5.5 + 3.06 ) x 2,000 / 12 = 1,420



Earthen Area (CN = 90 ) ( 1.9 + 2.36 ) x 5.00 x 3,630 = 77,359



Design Runoff Volume = 80,120(cubic feet)

Storage Volume Computations

Design Runoff Volume: 80,120(from calculations above)

Manure Solids Volume: 0(Multiply tons/year by 50 cu. ft./ton)

Other Solids Volume: 0

Liquid Manure Volume: 0(Divide gal/year by 7.5 gal/cu. ft.)

Process Wastewater Volume: 97,333(Divide gal/year by 7.5 gal/cu. ft.)

Total Volume Required: 177,453(cubic feet)

Approximate Design Dimensions Depth: 8 Width: 150 Length: 200(select dimensions from Table 8c that result in a pond volume equal or greater than the required volume)

Volume: 178,944(cubic feet)


However, a complete engineer’s evaluation ...

results in a smaller pond, reducing cost ~ $4,000 for Frank

Job Name: Frank's Dairy Computed By:

Location: Fort Morgan, CO Date 12/18/00Climate Station: Fort Morgan, 3038

BASIC DATA REQUIRED POND VOLUME STORAGE POND DESIGN DATA

Solids & Slurry Inflow : 0 cu. ft. /day Bottom Width: 102 ft. Top Width: 150Other Liquid Waste Inflow: 2000 gal. /day Residuals Storage: 46,555 cu.ft. Bottom Length: 110 ft. Top Length: 158

Contributing Roof Area: 1,000 sq. ft. 25yr. Storm Runoff: 45,184 cu.ft. Inside Slope: 3 H:1V Total Depth: 8Contributing Concrete Lot Area: 2,000 sq. ft. (CN 97) Design Volume: 91,739 cu.ft. Design Depth: 6 ft. Design Surface Area: 23,700

Contributing Earth Lot Area: 192,000 sq. ft. (CN 90) Evaporation Area: 11220 sq. ft Storage Volume: 92,80825yr-24hr Precipitation Depth: 3.4 inches Available Storage: 101% of design Freeboard: 2 ft. Freeboard Volume: 40,104

Annual FWS Evaporation: 48.0 inches Seepage Rate: 0.000 in./day Total Volume: 136,608

INFLOW OUTFLOW STORAGEMonthly Contribution from Precipitation Waste Inflow Total Surface Seepage Planned Total Monthly

Precip. Earth Lot Concrete Lot Roofed Area On Pond Solids Liquids Inflow Evaporation Loss Drawdown Outflow In - OutMonth (inches) % P (cu. ft.) % P (cu. ft.) % P (cu. ft.) (cu. ft.) (cu. ft.) (cu. ft.) (cu.ft.) (inches) (cu. ft.) (cu. ft.) (acre-in.) (cu. ft.) (cu. ft.)

Jan. 0.25 10% 400 22% 9 100% 21 494 0 8,278 9,201 1.44 1,346 0 0 1,346 7,855Feb. 0.22 10% 352 18% 7 100% 18 435 0 7,477 8,288 1.68 1,571 0 0 1,571 6,717Mar. 0.66 10% 1,056 30% 33 100% 55 1,304 0 8,278 10,725 2.64 2,468 0 0 2,468 8,257Apr. 1.26 10% 2,016 40% 84 100% 105 2,489 0 8,011 12,704 4.32 4,039 0 16 62,119 -49,415May 2.61 18% 7,517 50% 218 100% 218 5,155 0 8,278 21,384 5.76 5,386 0 0 5,386 15,999June 2.04 18% 5,875 46% 156 100% 170 4,029 0 8,011 18,241 6.96 6,508 0 0 6,508 11,734July 1.85 17% 5,032 45% 139 100% 154 3,654 0 8,278 17,256 7.20 6,732 0 0 6,732 10,524Aug. 1.39 14% 3,114 45% 104 100% 116 2,745 0 8,278 14,357 6.48 6,059 0 0 6,059 8,298Sep. 1.03 15% 2,472 45% 77 100% 86 2,034 0 8,011 12,680 4.80 4,488 0 16 62,568 -49,888Oct. 0.69 13% 1,435 42% 48 100% 58 1,363 0 8,278 11,181 3.36 3,142 0 0 3,142 8,040Nov. 0.39 10% 624 25% 16 100% 33 770 0 8,011 9,454 1.92 1,795 0 0 1,795 7,658Dec. 0.28 10% 448 25% 12 100% 23 553 0 8,278 9,314 1.44 1,346 0 0 1,346 7,967

Totals: 12.67 30,341 903 1,056 25,023 0 97,463 154,786 48 44,880 0 32 161,0401.90 inches 5.42 inches 12.67 inches


Documents

Section 8 - Wastewater Storage Pond Design Colorado CNMP Workshop Wastewater Storage Pond Design Prepared by J.E. Andrews, PE, NRCS - Lakewood, CO