O.L.D. M

CDONALD H

AS A

FARM (P

T. 2)

BY :

DE

XT

ER

SM

I TH

& J

ES

US

CO

VA

RR

UB

I AS

SITUATION• Mr. Oswald Leopold Dermot McDonald,

better known as O.L.D. McDonald, read our proposal for the pond he wanted

• After careful consideration decided he wants a subsurface drainage system instead

• Mr. McDonald has again provided us with boundary, elevation, and soil data in order to create this system.

• Spare no expense for the system.

OBJECTIVES

• How to create a soil and contour map

• Help Old McDonald by developing a subsurface drainage system.

COMPONENTS

• Outlets

• Sub-surface Main drains

• Sub-surface Laterals

• MapWindows 4.8.6 (recommended)

HOW TO CREATE A SOIL/CONTOUR MAP

1.You need to convert the soil and boundary layers to universal transverse Mercator (UTM) so that it measures distances rather than angles.

2.Open up MapWindows 4.8.6 and add the two layers we will convert.

…SOIL/CONTOUR MAP CONTINUED 1

3. Select toolbox> reproject shape FILE>North America> NAD83> UTM 16>Zone 16>

…SOIL/CONTOUR MAP CONTINUED 2

4. Open new project (YOU MAY BE PROMTED TO SAVE BUT PLEASE DO NOT!)>Add layer>Open only UTM Layers

…SOIL/CONTOUR MAP CONTINUED 3

5. After adding the reprojected shape files we need to add and generate the elevation file into a contour shapefile.

6. Go to

toolbox>Generate contour shapefile (make sure the contour shape interval=1)>Generate

…SOIL/CONTOUR MAP CONTINUED 4

7. After the contour file is made we must label both the soils and the contours.

8. For the soil layer, we must first categorize the soil polygons. To do so Double click the soil layer> categories>check unique values > Fields=MUSYM > select a color scheme> Generate

…SOIL/CONTOUR MAP CONTINUED 5

9. After categorizing the soil layer we must name the soils in the layer information table.

10.To do so click table > click edit > add field> select string type.

11.Soil names can be obtained by using the Web soil Survey and using the MUSYM to identify.

…SOIL/CONTOUR MAP CONTINUED 6

12. To label the soils by name, you click the little label symbol at the end of the layer, opening the label menu.

13.After selecting the “soil_name” field and inserting it the expression field, you can check “Labels Visible” to show them on the map. Then click “ok”

14.For the contour labels you add the “Grid_Value” field in the expression

FINDING NATURAL SLOPES

MAINS AND DRAINS

• Place drains at lowest possible elevation

• Two drain, two main system

• Second main allows drainage from northeastern corner

• Mains should go along the natural occurring “valleys”.

DETERMINING SPACING OF LATERALS

DETERMINING SPACING OF LATERALS CONT.

LATERALS

• Should catch downward slopes towards the main for best water movement.

• Slopes on laterals 21-24 steeper than laterals on Main 1

SIZING THE LATERALS AND MAINS• Acreage surrounding the

laterals determines the discharge rate.

• In order to size the laterals, both discharge rate or area along with slope are determining factors.

• Since spacing is 120ft and the laterals have a specified length, you can calculate the acreage that each lateral has to drain

Note: Recommends 3in tile, but sometimes its safe to use one size up for security.

SIZING THE LATERALS AND MAINS• Our method of sizing allows for

gradual increase in size as accumulated length of laterals feeding into the main along with the length of them main, saving money

• But O.L.D. McDonald doesn’t care about cost and would rather be safe in sizing.

• So... we will take the total length of the system which includes the length of every lateral and the length of the main to size it using the following chart.

CAPACITY OF TILE IN ACRESDrainage Coefficient (in/day): 0.375

Drain Spacing (ft): 120 Pipe Type Index: 1

SIZE (in) 4 5 6 8 10 12 15 18Roughness 0.015 0.015 0.015 0.015 0.017 0.017 0.020 0.020GRADE

(f t per 100')

0.05 3 5 7 15 24 39 60 98

Tile Length 1,090 1,820 2,550 5,450 8,720 14,160 21,780 35,580

0.10 4 7 10 22 34 55 85 138Tile Length 1,460 2,550 3,630 7,990 12,350 19,970 30,860 50,100

0.15 5 8 12 26 42 68 104 169Tile Length 1,820 2,910 4,360 9,440 15,250 24,690 37,760 61,350

0.20 5 9 14 30 48 78 120 195Tile Length 1,820 3,270 5,090 10,890 17,430 28,320 43,560 70,790

0.25 6 10 16 34 54 87 134 218Tile Length 2,180 3,630 5,810 12,350 19,610 31,590 48,650 79,140

0.30 6 11 17 37 59 95 147 239Tile Length 2,180 4,000 6,180 13,440 21,420 34,490 53,370 86,760

0.35 7 12 19 40 64 103 159 258Tile Length 2,550 4,360 6,900 14,520 23,240 37,390 57,720 93,660

0.40 7 13 20 43 68 110 170 275Tile Length 2,550 4,720 7,260 15,610 24,690 39,930 61,710 99,830

0.45 8 13 21 45 72 117 180 292Tile Length 2,910 4,720 7,630 16,340 26,140 42,480 65,340 106,000

Maximum drainage area (acres) corresponding to the size of main and the gradeLength of lateral (feet) required for the drained area given the spacing

Generic Plastic

SIZING THE LATERALS AND MAINS• Main 1 Length

= 14400 ft.• Main 2 Length

= 4150 ft. • As grade

increases, the tile will be able to move more water.

• Its best to use a lower grade on the chart to use as a minimum

• Main 1 grade= .21

• Main 2 grade= .48

SIZING THE LATERALS AND MAINSSegment Area Drained (Acres) length (ft) Delta Height (ft) Slope (%) Tile Size

Main 1 95 2400 5 0.21 10Lat 1 1.3 480 1.5 0.31 4Lat 2 1.3 480 1 0.21 4Lat 3 1.3 480 1 0.21 4Lat 4 1.3 480 2 0.42 4Lat 5 1.3 480 1 0.21 4Lat 6 1.3 480 2 0.42 4Lat 7 1.3 480 1.5 0.31 4Lat 8 1.3 480 1.5 0.31 4Lat 9 1.3 480 2 0.42 4Lat 10 1.3 480 2 0.42 4Lat 11 2.0 720 3 0.42 4Lat 12 2.0 720 3.5 0.49 4Lat 13 2.0 720 3.5 0.49 4Lat 14 2.0 720 3.5 0.49 4Lat 15 2.0 720 2.5 0.35 4Lat 16 2.0 720 2.5 0.35 4Lat 17 2.0 720 2.5 0.35 4Lat 18 2.0 720 2.5 0.35 4Lat 19 2.0 720 2 0.28 4Lat 20 2.0 720 2 0.28 4Main 2 17.8 1550 7.5 0.48 5Lat 21 1.8 650 4 0.62 4Lat 22 1.8 650 3 0.46 4Lat 23 1.8 650 3 0.46 4Lat 24 1.8 650 3 0.46 4

Item Amount Cost Total Cost10" tile 2400 $2.65 $6,360.004" tile 14600 $0.75 $10,950.005" tile 1550 $0.90 $1,395.00

4" tap tee 24 $4.73 $113.52$18,818.52

$164.64Grand Total

Cost/Acre (114.3 acres)

PRICING OF SYSTEM

THINGS TO CONSIDER

• A subsystem will only function as well as its outlet.

• Be sure to choose a suitable one for your system

• Make sure that the system can actually be formed or constructed

Questions?