How-To Tips
Formulas
Waterfall Volume Estimating
If the water depth at the weir edge is 1/2 inch, then the flow is approx. 25 gal/min per foot of width. Example: You need a 3/4" deep flow over the 30-inch wide weir. 25 gal/min x 1-1/2 (for 3/4”) x 2-1/2 (for 30 inch width) = 94 gal/min.
Area
Rectangle/Square: multiply the length of one side by the length of an adjoining side. Circle: multiply the radius (distance from the center to the edge) by itself and then by 3.1416 Ellipse (oval): multiply the distance from the center to the nearest side by the distance from the center to the furthest side, and multiply that by 3.1416.
Volume
Calculate the area (above) and multiply by the average depth. If all numbers are in feet, then the result will be cubic feet. Multiply that by 7.4805 for the number of gallons.
Flow From A Pipe
To estimate the approximate volume of water flowing from a vertical round pipe: Gal/min = multiply the square root of the height of the water above the end of the pipe by .9 by the actual inside diameter of the pipe (= diameter squared) by 5.7.
To estimate the approximate volume of water flowing through a pipe: Gal/min = 0.0408 multiplied by the actual inside diameter of pipe in inches multiplied by the actual inside diameter of pipe in inches (diameter squared) multiplied by feet/min of water velocity. Note: it is recommended that the velocity never exceed 300 feet/minute (5 feet/second).
Pump Horsepower To Raise Water
NOTE: This applies to larger pumps only. Horsepower = gallons per minute multiplied by total head in feet divided by 3960
Water
1 gallon of water = 8.33 lbs. = 231 cubic inches
1 lb. of water = 27.7 cubic inches
1 cubic foot of water = 7.4805 gallons = 62.4 lbs.
Operating Costs
Calculate: gal/min multiplied by head in feet multiplied by $/kilowatt-hour multiplied by 0.746. Divide that by the result of: % pump efficiency multiplied by % motor efficiency multiplied by 3960.
Design Data
1. QUICK PIPE SIZING GUIDE for pressure flows with appr. 3.0m/0.3bar/10’/3.34kpa pressure drop per 30m / 100 feet of pipe.
PIPE SIZE: 1” 1 1/4” 1 1/2” 2” 3” 4” 6” 8” 10” 12”
FLOW/USGPM: 9 19 28 52 200 380 880 1600 2400 3500
FLOW/L/min: 34 72 106 197 757 1438 3330 6056 9084 13247
DO NOT USE PRESSURE FLOW TABLES FOR GRAVITY (RETURN) FLOWS, use sewer flow tables!
2. QUICK SIZING GUIDE FOR PERFORATED SUCTION STRAINERS WITH 40%+ OPEN AREAS
Opening size to be appr. 50% of nozzle orifices.
SCREEN OPENINGS: 1mm 1.5mm 2mm 3mm 4mm 6mm 10mm
FLOW L/min per m2: 220 380 530 740 950 1200 30000
SCREEN OPENINGS: 0.063” 0.125” 0.250” 0.375” 0.500” 0.750”
FLOWUSGPM per square foot: 12 17 25 50 100 270
3. ANTI VORTEX COVERS OVER PUMP SUCTION FITTINGS
Required in most installations to prevent entry fair into system by vortexing. Size depends on water depth and flow.
4. NPSHA: (NET POSITIVE SUCTION HEAD AVAILABLE):
Term describing the depth of water over the pump suction required to permit pump to perform as advertised, the pump supplier usually furnishes
this information, which is essential during design/engineering of a pump system.
5. SURGE/SPLASH COLLAR: Structural part of a pool or device that encloses the falling water of a spray effect to prevent content of pool to
surge and cause spray effect to jump especially in circular or square pool.
6. BALANCED OVERFLOW: An overflow that is sized to remove the greatest possible inflow into a pool before the pool overflows, usually sizing is
done to draw off the full flow of water supply into a pool (2 x #1 on this page). Sizing of overflow is done by establishing linear weir length of
overflow device (multiply pipe diameter x 3.14) and possible head of water before pool overflow can occur, then check waterfall data below for
flow rates. For very large pool and / or inflows consider an appropriate length overflow weir in front of a suitable size drain in the pool floor. In
multi level pools or cascades the overflow to be sized for the entire water surface area and set above non operating water level into base pool.
7. TO ESTIMATE APPR. 60 Hz PUMP HP / KW FOR A KNOWN PERFORMANCE:
(Flow in USGPM X MC (total, in feet head)) DIVIDE BY: 2970 or (3960 x 75% of known Efficiency): HP, x 1.34 : KW
TO ESTIMATE APPR. 50 Hz PUMP HP / KW FOR A KNOWN PERFORMANCE:
(Flow in L/min X MC (total, in meter head) DIVIDE BY: 2970 or (3960 x 75% of known Efficiency): HP, x 1.34 : KW
(Final engineering calculations might differ from above, as other factors and/or variations are to be considered.)
8. APPROXIMATE COSTS OF OPERATING A PUMP: Based upon the hourly operating costs of an electrical motor:
MULTIPLY KNOWN KWH COSTS X FACTORS SHOWN:
1 PHASE HP: 1/3 1/2 3/4 1 2 3 5
KW: 1.34 2.68 4.02 6.70
FACTOR: .408 .535 .760 1.0 2.0 2.95 4.65
3 PHASE HP: 1 3 5 10 20 30 50 100
KW: 1.34 4.02 6.7 13.4 26.8 40.2 67.5 135
FACTOR: .96 2.7 4.5 9.0 16.9 25.0 41.3 81.5
9. PERFORMANCE DIFFERENCES BETWEEN 50 Hertz & 60 Hertz (Cycles) ELECTRICAL MOTORS:
Pumps with 50 Hz motors have an appr. 19% lower performance than with 60 Hz motors.
Pumps with 60 Hz motors have an appr. 16% higher performance than with 50 Hz motors.
10. CONVERSION DATA:
FLOW: WEIGHTS OF WATER:
1L/min (LPM): .264 USGPM .220 IGPM 1 Kg or 1 Liter : 2.207 lbs
1 USGPM (G): 3.785 L/min 0.833 IGPM 1m3 : 1000 kg / 2203 lbs
1 IGPM: 4.546 L/min 1.2 UGSPM 1 cbft : 62.4 2 lbs / 28.28 kg
1 L/sec.: 15.85 USGPM 13.2 IGPM 1 US Gallon : 3.785 kg 8.36 lbs
1m3/min: 264.2 USGPM220.08 IGPM VOLUMES OF WATER: (M3: Cubic meter)
PRESSURE: 1M3 : 1000 Liter/35.31 cbft
1m/head (MC): 0,1 bar/9.82kpa/3.28’head/1.422PSI 1 cubic foot : 28.316 Liter/7.4805 US Gallons
1’head (FT): 0.305m/2.99kpa/0.0305bar/0.433PSI 1 Liter : 0.001 M3/0.353cbft
DISTANCE/HEIGHT/DEPTH: TORQUE: (Tightening of facering bolts of light fixtures)
1 Meter: 39.37 Inches (“) / 3.28083 Feet (‘) 1 (Newton Meter) NM : 8.85 Inch Lbs
1 Inch (“): 25.4 mm 1 (inch pound)” lbs : 0.12 NM
1 Foot (‘): 30.4801cm LUMINANCE OF ILLUMINATION:
AREA: 1CP, Candle Power per square foot : 10.764 CP/m2
1 m2: 10.76 Square Feet (sq ft) 1 CP, Candle Power per square inch : 1550.0 CP/m2
1 sq ft: 0.0929 m2 1 LM, Lumen per square foot : 10.763 LM/m2
11. BACK THRUST OF JET: (Using a pilot tube to measure nozzle pressure)
CLEARSTREAM JETS: Multiply nozzle orifice area X Exhaust (Nozzle) Pressure
AERATED JETS: Multiply (Center line only) internal exhaust jet orifice area X exhaust pressure.
WATER SCREEN JET 1854: 100 mm2 X Exhaust pressure
12. WATERFALLS (‘A’: Height of water overflowing over weir)
Suggested flow volumes per linear meter of waterfall, waterwall or overflow.
A’ L/min Suggested maximum free fall height
7mm 150 1.0m
10mm 250 1.2m
15mm 380 1.5m
20mm 510 1.8m
30mm 690 2.4m
40mm 1100 3.0m
50mm 1500 3.5m
Installing Pond Liner
The first physical part of building it, is digging the hole, making sure that the top edge is absolutely level. We recommend the use of a length of clear tubing filled with colored water to assure a perfectly level edge. It is critical that the surrounding edge is absolutely level - so that the liner will not show.
The hole should have steep sides, with no plant shelf, and a flat bottom. It also has to be constructed out of materials that will not harm the liner. If the soil is clay, smoothing it while wet will produce a pottery bowl that is ideal. Merely chop any roots well back and cover with wet clay. If the soil contains sharp rocks, use a non-biodegradable underlayment.
Once the hole is properly prepared, the liner is carefully positioned and is filled with water. It is an excellent idea to measure the water as it fills and make a permanent record as to how many gallons fills it to how high. This allows you to determine how many gallons are in the pond at specific levels for medication purposes, etc. As the pond fills, carefully fold the liner on the sides for a neat appearance. You can then drain the pond down far enough to secure the overlap behind the liner with the proper tape to make almost invisible folds.
To decorate the edge, we recommend that you use very clean thin fieldstones. The first layer, the larger ones, should overhang the pond by an inch or two; and, the top layer, the smaller ones, should cover the spaces between the first layer's stones. Be sure to line up the back edges of the two layers. Then lift the edge of the liner up and create a structural dam behind it - against, and about 2/3rd's the height of the two layers of rocks.
This berm is to keep surface water running across the ground from entering the pond, and should be made of a hard durable material - fiber reinforced concrete is ideal. The liner edge is then flipped over the berm and the area over it, and the outside of the pond is covered with a porous ground cover such as pine bark, pine straw, or river pebbles. Your ground cover should wind up snug against the back of the fieldstones and level with them. Fill to overflowing.
The result of this design is that you will have a pond to be proud of. It will appear to be flush with the surrounding ground, not looking like a pile of rocks, and the water is just barely below the top of the rocks. The water is actually well above ground level.
• RULE #I: THE POND EDGE MUST BE LEVEL.
• RULE #2: NEVER, EVER, WALK ON THE LINER – WITH SHOES ON
