1、 ANSI/ASAE EP302.4 FEB1993 (R2012) Design and Construction of Surface Drainage Systems On Agricultural Lands in Humid Areas American Society of Agricultural and Biological Engineers ASABE is a professional and technical organization, of members worldwide, who are dedicated to advancement of engineer
2、ing applicable to agricultural, food, and biological systems. ASABE Standards are consensus documents developed and adopted by the American Society of Agricultural and Biological Engineers to meet standardization needs within the scope of the Society; principally agricultural field equipment, farmst
3、ead equipment, structures, soil and water resource management, turf and landscape equipment, forest engineering, food and process engineering, electric power applications, plant and animal environment, and waste management. NOTE: ASABE Standards, Engineering Practices, and Data are informational and
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6、 Newly developed Standards, Engineering Practices and Data approved after July of 2005 are designated as “ASABE“. Standards designated as “ANSI“ are American National Standards as are all ISO adoptions published by ASABE. Adoption as an American National Standard requires verification by ANSI that t
7、he requirements for due process, consensus, and other criteria for approval have been met by ASABE. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means
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9、ASABE require that action be taken periodically to reaffirm, revise, or withdraw each standard. Copyright American Society of Agricultural and Biological Engineers. All rights reserved. ASABE, 2950 Niles Road, St. Joseph, Ml 49085-9659, USA, phone 269-429-0300, fax 269-429-3852, hqasabe.org ANSI/ASA
10、E EP302.4 FEB1993 (R2012) Copyright American Society of Agricultural and Biological Engineers 1 ANSI/ASAE EP302.4 FEB1993 (R2012) Approved August 1993; reaffirmed February 2013 as an American National Standard Design and Construction of Surface Drainage Systems on Agricultural Lands in Humid Areas D
11、eveloped by the ASAE Surface Drainage Committee; approved by the ASAE Soil and Water Division Steering Committee; adopted by ASAE as a Recommendation December 1966; revised March 1972, March 1973; reconfirmed December 1977; reconfirmed and reclassified as an Engineering Practice December 1978; recon
12、firmed December 1983, December 1984, December 1985; revised December 1986; reconfirmed December 1991; revised February 1993; approved as an American National Standard August 1993; reaffirmed by ASAE December 1997, December 1999; reaffirmed by ANSI June 2000; reaffirmed by ASAE January 2001, February
13、 2003; reaffirmed by ANSI February 2003; reaffirmed by ASABE and ANSI February 2008; reaffirmed by ASABE December 2012; reaffirmed by ANSI February 2013. Keywords: Drainage, Erosion, Humid, Surface 1 Purpose 1.1 This Engineering Practice is intended to improve the design, construction and maintenanc
14、e of surface drainage systems which are adapted to modern farm mechanization. It is limited to agricultural or farm-size areas, 259 ha (640 ac) or less, in the humid region of the eastern USA (see Figure 1). Figure 1 Key map for drainage curves (Humid areas for eastern USA where surface drainage may
15、 be needed) 1.2 Surface drainage is normally required for efficient crop production on slowly permeable soils with restrictive topography. It is not required when excess water is removed naturally. Typical problem areas are glaciated areas, coastal plains, bottomlands, deltas, and old lake beds. Sur
16、face drainage may eliminate the need for subsurface drains under certain conditions. Surface drains also apply to farm mains used to collect water from field drains and subsurface drains. ANSI/ASAE EP302.4 FEB1993 (R2012) Copyright American Society of Agricultural and Biological Engineers 2 2 Normat
17、ive References The following standards contain provisions which, through reference in this text, constitute provisions of this Engineering Practice. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Engineeri
18、ng Practice are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. Standards organizations maintain registers of currently valid standards. ASAE S268.4, Design, Layout, Construction and Maintenance of Terrace Systems ASAE S526, Soil and Wa
19、ter Engineering Terminology 3 Definitions and Terminology 3.1 The following terms used in this Engineering Practice are defined in ASAE S526: bedding berm crowning diversion field drain field lateral interceptor drain land grading parallel system reverse grade row drain row grade surface drainage wa
20、ter leveling 3.2 For the purpose of this Engineering Practice only, the following terms are defined herein: 3.2.1 land smoothing: The process of smoothing the land surface with a land plane or land leveler to eliminate minor depressions and irregularities without changing the general topography. 3.2
21、.2 cross slope: The slope perpendicular to crop rows. 3.2.3 farm main: An outlet ditch serving an individual farm. 3.2.4 pipe drop: A pipe, with or without headwalls, used as an erosion control structure at a transition to drop water into a deeper drain. ANSI/ASAE EP302.4 FEB1993 (R2012) Copyright A
22、merican Society of Agricultural and Biological Engineers 3 3.2.5 random system: A system of meandering row drains, field drains, and/or field laterals that are located in and drain depressions in a field. 3.2.6 transition: The outlet section of a drain that discharges into a deeper drain. Transition
23、s may be vegetated or nonvegetated sections, or erosion control structures. 4 Principles 4.1 The objectives of surface drainage are: a) to prevent water from ponding on land surfaces or in surface drains that are crossed by farm equipment; b) to remove excess water in time to prevent damage to crops
24、; c) to accomplish the above without excess erosion. 4.2 Complete drainage systems shall be planned and designed with all aspects considered. The collection system, consisting of the land surface and shallow drains, removes excess surface water from individual areas within fields. The disposal syste
25、m, consisting of somewhat larger ditches, receives drainage water from the collection system and removes it from the land. Transitions, including structures, that permit drains to discharge into larger or deeper drains must provide for adequate erosion control without holding water on field surfaces
26、 for excessive periods of time. The system shall be designed as an integral part of the soil and water facilities, the farm layout, and cropping plan. Farm roads shall be planned to complement the drainage system and to facilitate farming operations. 4.3 There are several methods of draining agricul
27、tural land. Land surfaces that pocket water can be drained by cutting and filling. Depressions can be drained by row drains, field drains, and field laterals. The methods can be combined, thereby reducing the number of depressions and the number of drains. A brief discussion of the principal surface
28、 drainage methods follows. 4.3.1 Land smoothing eliminates minor depressions and irregularities in a field, thereby improving surface drainage and increasing farm machinery efficiency. Frequently, this is an interim measure that will be replaced by land grading when economic conditions permit. 4.3.2
29、 Land grading, by carefully designed cutting and filling operations, provides excellent surface drainage. 4.3.3 Water leveling was developed for fields which are to be flooded and provides adequate drainage for rice and other selected, close growing, water tolerant crops. 4.3.4 Random drainage syste
30、ms provide for drainage of the low areas by row drains, field drains, and field laterals. These systems are relatively low in cost and give a high return on the investment. They require frequent maintenance and may be obstacles to farm machinery, particularly if drains are closely spaced. On severel
31、y undulating topography, random drainage may be the only economical system. 4.3.5 Parallel drainage systems facilitate mechanization by eliminating short rows and point rows. Crossable field drains or row drains are constructed between parallel field laterals. This permits farm equipment to travel g
32、reater distances without turning. Field surfaces between field laterals should be improved by land smoothing or land grading for maximum benefits. 4.3.6 Bedding, under most conditions, is not considered an acceptable drainage practice for row crops because rows adjacent to the dead furrows will not
33、drain satisfactorily. It is an acceptable practice for hay and pasture crops in some areas. Normally there is some crop loss in and adjacent to the dead furrows. 4.3.7 Crowning was developed for sugar cane production in areas that formerly had ample hand labor; is well established in some areas and
34、provides excellent drainage. Crowning requires more maintenance than most of the other systems. The large number of field laterals take land out of production, and they are a source ANSI/ASAE EP302.4 FEB1993 (R2012) Copyright American Society of Agricultural and Biological Engineers 4 of erosion and
35、 sedimentation, and weed and grass infestation. Crowning with crossable field laterals provides excellent drainage for the pasture crops commonly grown in the sugar cane areas. 4.3.8 Diversions intercept upland runoff and prevent it from overflowing bottomlands. This simplifies installation of drain
36、age systems on bottomlands. 4.3.9 Interceptor drains intercept and remove subsurface water. They are used on long slopes with 1% or steeper grades and shallow, permeable surface soils overlying relatively impermeable subsoils. 5 Design 5.1 Surface drainage system design criteria are based on the ass
37、umption that all lands to be drained will be suitable for agricultural use after drainage. Design shall consider construction and maintenance needs and irrigation requirements where applicable. The rate of water removal, in terms of depth per unit of time to be provided by the drainage system, depen
38、ds on several interrelated factors such as rainfall characteristics, soil properties, and cropping patterns. For most row crops, surface drainage systems shall complete removal of excess water from the soil surface within 24 h after rainfall ceases. More rapid removal may be necessary for high-value
39、 truck crops. A longer time is permissible for grasslands and woodlands. 5.2 The intensity of drainage desired is expressed in terms of drainage curves (see Figures 1, 2, and 3). These empirical curves were developed from a large number of field measurements of drainage flow rates and observations o
40、f the adequacy of drainage. The curves will not provide for peak flows from large storms. Excess runoff will be discharged as overland flow temporarily flooding adjacent lands. Curves with the higher coefficient values represent a larger drainage capacity. Figure 2 Drainage curves northern area of U
41、SA (see Figure 1). Source based on USDA SCS National Engineering Handbook, section 16, chapter 6. ANSI/ASAE EP302.4 FEB1993 (R2012) Copyright American Society of Agricultural and Biological Engineers 5 Figure 3 Drainage curves southern area of USA (see Figure 1). Source based on USDA SCS National En
42、gineering Handbook, section 16, chapter 6. 5.2.1 The drainage curves are applicable to drainage areas having average slopes of less than 4.7 m/km (25 ft/mile). 5.2.1.1 The basic equations used to describe the drainage curves of Figures 2 and 3 are of the form: Q = K1CM5/6, One exception is curve 2B
43、which is Q = K2CM0.7, where: Q is design discharge, m3/s (ft3/s); K1= unit conversion factor equal to 0.06 if in SI metric units and 1 if in inch-pound units; K2= unit conversion factor equal to 0.0534 if in SI metric units and 1 if in inch-pound units; C = coefficient relating to desired level of d
44、rainage. Numerical values for the coefficient are shown on figures 2 and 3; M = drainage area, ha (ac). 5.2.2 Figure 1 shows the extent of the humid area of the eastern USA where surface drainage may be needed. Regional areas are delineated to show coverage of Figures 2 and 3. ANSI/ASAE EP302.4 FEB1
45、993 (R2012) Copyright American Society of Agricultural and Biological Engineers 6 5.2.3 Figure 2 is for the northern regional area: curve 2B for excellent farm drainage; curve 2C for good farm drainage (basic curve for grain crops); curve 2D for fair drainage (basic curve for improved pastures); cur
46、ve 2M for agricultural drainage in the Red River Valley in Minnesota, North Dakota, and South Dakota. NOTE: No recommendation is made for woodland drainage. 5.2.4 Figure 3 is for the southern regional area: curve 3A for row-crop drainage in the gulf coastal and coastal plains area; curve 3B for row-
47、crop drainage in the deltas and bottomlands of the major rivers; curve 3C for improved pasture drainage; curve 3D for irrigated ricelands; curve 3E for upland range and unimproved pasture drainage; curve 3F for gulf coast marsh and marsh range, and woodland drainage. 5.2.5 The value for M should be
48、determined for each separate drainage component. For each row drain, this would be that amount of land drained by it. For each collector component, such as field drain, field lateral and farm main, the value for M would be the total area drained by the system. 5.3 Ditch design 5.3.1 Field drains (se
49、e Table 1 and Figure 4) are located at the lower ends of field rows, through surface depressions, above barriers that trap runoff, and where required to divert runoff from lower areas. Drains located at or near soil changes provide locations for field roads, permitting the soils to be managed differently during farming operations. Field drains need not be designed to contain the quantities of flow indicated on the drainage curves, as their primary purpose is to remove residual surfa
