Rice Flood Guide

Filed Under:

Publication Number: F0810

This guide will help you determine the pumping time required to flood a certain field to a 4" depth. The values listed are not absolute; they do not take into consideration losses that may occur due to soil type, field configuration, crop and weather demand, or other factors that may affect the flow in the field.

The guide will help save as much water as possible and keep pumping costs in line. Other guidelines for rice irrigation are also listed.

Basis: 4"/Acre Flood
Total Seasonal Water Use: 23" -- 26"
Average Daily Water Use: 0.25"/Day

Fuel Consumption per Acre-inch

Diesel	50' Lift - 0.45 gallons/Acre-inch 75' Lift - 0.70 gallons/Acre-inch 100'Lift - 0.90 gallons/Acre-inch
Electric	50' Lift - 6.4 KWH/Acre-inch 75' Lift - 9.6 KWH/Acre-inch 100' Lift - 12.8 KWH/Acre-inch

Well Size
Minimum - 8 gpm/Acre
Maximum - 30 gpm/Acre

Well Capacity
Acre-inches per hour=GPM/450

Pumping time to replace daily water use of 0.25" based on total pumping time required for initial flood of 4 inches.

Pumping Time (hours)**
4" Flood	0.25" Daily Use	4" Flood	0.25" Daily Use
60	3.8	150	9.4
70	4.4	160	10.0
80	5.0	170	10.6
90	5.6	180	11.3
100	6.3	190	11.9
110	6.9	200	12.5
120	7.5	210	13.1
130	8.1	220	13.8
140	8.8	225	14.1

**Example: It takes between 8.1 - 8.8 hours daily pumping to replace the 0.25" on the basis that it takes between 130 and 140 hours total to pump 4" on the whole field.

Daily water use is an average value for the whole season; peak water use is approximately 0.30" per day. This will occur during late vegetative and reproductive periods, so you may need to adjust pumping times to meet this higher demand period.

Total Hours Pumping Time for a 4-Inch Flood
GALLONS PER MINUTE (GPM)
GPM	400	600	800	1000	1200	1400	1600	1800	*2000	2200	2400	2600	2800	3000	3500	4000
	45																10
	90	60															20
	135	90	68	54													30
	180	120	90	72	60												40
	225	150	112	90	75	64	56										50
H		180	135	108	90	77	68	60									60
		210	158	126	105	90	79	70	63	57							70
	O	240	180	144	120	103	90	80	72	65	60						80
			202	162	135	116	101	90	81	74	68	62					90
		U	225	180	150	128	112	100	90	82	75	69	64	60			100
				198	165	141	124	110	99	90	82	76	71	66			110
			R	216	180	154	135	120	108	98	90	83	77	72	62		120
				234	195	167	146	130	117	106	98	90	84	78	67	58	130
				S	210	180	158	140	126	114	105	97	90	84	72	63	140
					225	193	169	150	135	123	112	104	96	90	77	68	150*
						206	180	160	144	131	120	111	103	96	82	72	160
						218	191	170	153	139	128	118	109	102	87	77	170
						231	202	180	162	147	135	125	116	108	93	81	180
							214	190	171	155	142	132	122	114	98	86	190
							225	200	180	164	150	138	128	120	103	90	200
								210	189	172	158	145	135	126	108	95	210
								220	198	180	165	152	141	132	113	99	220
								230	207	188	172	159	148	138	118	104	230
									216	196	180	166	154	144	123	108	240
									225	204	188	173	161	150	128	113	250
										225	209	190	117	165	141	124	275
											225	208	193	180	154	135	300
												225	209	195	167	146	350
													225	210	180	158	350
														225	193	169	375
															206	180	400
															218	191	425
															231	103	450
																214	475
																225	500

*Example: With 2000 gallons per minute on 150 acres it takes a minimum of 135 hours to pump 4" on the whole filed. Average daily water use is 0.25"/day.

When flooding a dry field, you will probably need to pump an additional inch of water to take care of soil requirements and leaks in levees. This will mean increasing pumping time by 25%.

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