Structure Sizing and Evaluation

CNMP Core CurriculumSection 2 – Farmstead Planning

Objectives• Critical storage interval.

• Calculate storage volume• Adequacy of existing storage and treatment

facilities• Investigation techniques

To Be Discussed:• Storage Volumes• Critical Storage Period• Evaluate Existing Structures

Storage Requirements• State Specific Requirements

– Section IV eFOTG –

– Timing for Environmentally Safe Manure Utilization• Active growing periods• Extension recommendations

State 313 Storage Period

Iowa 120 days min425 days max (14 m)

Nebraska 180 days

Kansas 120 days

• Rainfall• Runoff • Process

Wastewater• Manure

Storage VolumeWaste Sources:

• Milking System Wash• Bulk Tank Wash• Clean-Up• Rinses During Milking • Wash Pen• Auto Back Flush • Sinks / Boot Wash• Washing Machine• Foot Bath• Plate Cooler• Flush System

Process Wastewater ExampleMilking Center Wastewater:

Dairy Flush Waste Collection System

Scrape collection – Tractor

Wastewater Storage Inspection

• Manure/Effluent Level– Sufficient Capacity for Runoff Event?– Regular Monitoring Early Detection

• Seepage Into or Out of the Structure

– Liquid Level Indicators Installed?• State Specific Requirements

Storage VolumeTypical Storage Pond -

In some states, the freeboard must be below the crest of the spillway. Check your state rules and regulations.

Emergency Storm Storage & Freeboard

• Storage for a 25 yr, 24-hr storm event– Direct precipitation– Runoff

• Freeboard – typically 1’ but can vary by state

Emergency Storm Storage

Free Board

Operating Level

Volume Calculations

• V = volume• r = radius• d = depth

drπV 2 ××=

• Cylindrical storage structures

Volume Calculations• Earthen Sloped Wall Structure

– Z = slope ratio– d = depth– BW = Bottom width– BL = Bottom length

( ) ( ) ( )dBLBWdBWZdBLZdZV ××+××+××+

××= 22

32

34

Volume Calculations• A Quick Way to Estimate Volume for sloped

earthen storage

((Areatop + Areabot)/2) x depth

Defining the “critical storage period”

The critical storage interval is the minimum storage period required to hold

all waste and rainfall between land application events

The Cropping System Will Define the Minimum Storage Interval

Storage Interval

Can the existing waste management and cropping

system be managed in a properfashion to accommodate a herd

of 175 lactating cows?

Example CNMP Dairy

Corn Silage Wheat Cover ForageJanuary FebruaryMarchApril PlantMay ActiveJune GrowingJuly Burn down PeriodAugustSeptember HarvestOctoberNovember PlantDecember

Example Dairy Cropping System

Corn Silage Wheat Cover ForageJanuary FebruaryMarch Application ApplicationApril PlantMay ActiveJune GrowingJuly Burn down PeriodAugustSeptember HarvestOctober Application ApplicationNovember PlantDecember

Example Dairy Cropping System

Monthly waste and rainfall runoff volumes are needed

Build an Inflow – Outflow Tablefor the waste storage structure

Inflow – Outflow Volumes: Holding Pond (ft3)Month Available

Volume –Beginning of

month

Waste Inflow AvailableVolume –

End of month

Application Volume

April 67,115 12,530 54,585 0May 54,585 13,260 41,325 0June 41,325 9,150 32,175 0July 32,175 13,100 19,075 0August 19,075 9,940 9,135 0September 9,135 9,600 (465) 67,580October 67,115 12,360 54,755 12,360November 67,115 16,630 50,485 0December 50,485 17,650 32,835 0January 32,835 17,480 15,355 0February 15,355 15,420 (65) 0March (65) 18,990 (19,055) 86,170

Storage Period VolumesStorage Period 1 Storage Period 2 Yearly Storage

TotalsNovember – March April – October(151 Days) (214 Days)

Gallons Gallons GallonsManure (50% of 175 lactating cows) 167,062 236,765 403,827

Bedding (Sawdust) 18,865 26,735 45,600Wash water(249 gal./day) 37,724 53,470 91,194

Silage leachate 7,630 7,630 15,260Runoff Trench Silo, 6,000sfFeed Bunk, 1,320sfconcrete lot, 13,000sf

269,280 312,984 582,264

Direct rainfall(precip-evap) 142,494 -39,414 103,080

Total 643,055 598,170 1,241,225

** Table does not include permanent storage, 25yr-24hr storm storage, or freeboard volume.

Storage Period VolumesStorage Period 1 Storage Period 2 Yearly Storage

TotalsNovember – March April – October(151 Days) (214 Days)Cubic Feet Cubic Feet Cubic Feet

Manure (50% of 175 lactating cows) 22,334 31,653 53,988

Bedding (Sawdust) 2,522 3,574 6,096Wash water(249 gal./day) 5,043 7,148 12,192

Silage leachate 1,020 1,020 2,040Runoff Trench Silo, 6,000sfFeed Bunk, 1,320sfconcrete lot, 13,000sf

36,000 41,843 77,843

Direct rainfall(precip-evap) 19,050 -5,269 13,781

Total 85,970 79,969 165,939

** Table does not include permanent storage, 25yr-24hr storm storage, or freeboard volume.

Storage required for the five month period from November – March = 644,000 gallons

86,000 cubic ft

Sample Dairy CNMPCritical Storage Interval

Storage required for the seven month period from April – October = 598,000 gallons

80,000 cubic ft

Storage Volume Sets Application Schedule !

• Existing Waste Storage

• Earthen Holding Pond:– Stores waste from freestall barn, loafing lot and all

runoff handled as waste at the Barr Dairy Farm

• Planning Volume ~ 502,000 gallons / 67,115 ft3

• Total volume – (freeboard, 25 yr, 24-hr storm + permanent storage)

Evaluate Existing Components• Storage Structure

Liners• Walls• Fences• Embankments• Size / Storage

Capacity of theStructure

Evaluate Existing Components

• Inlet Pipes• Ramps• Clean Water

Diversion• Resource

Concerns– Existing soils

• Water table• Gravel• Karst soils

Earthen Storage Inspection• Liner Erosion

– Wave action– Manure inlets and

agitation points– Rainfall– Burrowing animals,

trees and large weeds– Is there a liner present?

Earthen Storage Inspection• Structural Integrity

– Pipes Through Structures

– Outside Toe and Sidewall of Berms

– Note Any Soft, Moist, Slumping Areas

– Background Data

Storage Inspection• Appearance

– Maintained• Cut vegetation• Remove trash

Storage Inspection• Safety

– Fenced to Limit Access

– Warning Signs– Pits Should Contain

an Escape Ladder– Permanent Cover

Over Pits

Storage Inspection• Records

– Required!!!– Early Detection of Problems– Verify Storage Period

Background Site Data• Evaluate Existing Soils

Data – Geologic Investigation• High Groundwater• Bedrock• Gravel• Hard Pan• Karst Topography• Sandy Soils

• If the Integrity of the Structure is Suspect, Investigate!

Soil Data Mart:http://soildatamart.nrcs.usda.gov/

Investigate!• Visual Inspection

– Can You See Evidence of Past Discharges?

• Evaluate Records

Liner Investigation• Does As-Built Exist?• Evaluate Liner Material

– Sample Existing Liner– Wetting Characteristics– Compaction

Water Balance

• Mass Balance Method• Storage = Qin-Qout- Seepage - Evaporation

– Pumping Records– Pan Evaporation

Evaluate Liner• Sampling

– Shelby Tube Hand Sampler

• ASTM D - 5084, Standard Test Method for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter.

Existing HoldingPond k Values

Sample # Orentation Density (pcf)

Natural Water %

k Value (cm/sec)

k Value (ft/day)

1W/F02-381 Vertical 89.2 31.6 1.8 x 10-8 0.000052

1S/F02-382 Vertical 91.4 30.8 1.6 x 10-8 0.000044 1/F02-383 Vertical 92.4 29.6 1.6 x 10-8 0.000046

2W/F02-384 Vertical 87.4 35.7 1.8 x 10-8 0.000051 2S/F02-385 Vertical 86.8 34.3 9.6 x 10-7 0.0027 2/F02-386 Vertical 87.8 30.2 1.2 x 10-7 0.00035

3/F02-387 Vertical 94.1 27.0 1.6 x 10-8 0.000045

4/F02-388 Vertical 95.8 26.7 6.1 x 10-8 0.00017

Seepage Meter

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Improper storage

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Improper storage

Reference Materials• USDA – NRCS. Part 651, AWMFH, Ch. 7

Geology and Groundwater and Ch. 10, Appendix 10D Geotechnical Design & Construction Guidelines.

• MWPS-18, Manure Storages, Section 2, 2001. Midwest Plan Service

• MWPS-36, Concrete Manure Storage Handbook, 1994 Midwest Plan Service

• American Concrete Institute. Building Code requirements for Reinforced Concrete, ACI 318-89 (Revised 1992).

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