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马清河灌区灌溉系统规划设计马清河灌区灌溉系统规划设计学校:扬州大学专业:水利水电工程班级:姓名:指导老师:目录TOCTOCTOC1基本资料 基本资料1.1概况灌区位于界荣山以南,马清河以北,总面积(20m等高线以下的)约12万亩。气候温和,无霜期长,适宜于农作物生长。年平均气温16.5℃,多年平均蒸发量1065mm,多年平均降水量1112mm,马清河灌区地形图见附图1。灌区人口总数约8万,劳动力1.9万。申溪以西属兴隆乡,以东属大胜乡。根据农业规划,界荣山上以林、牧、副业为主,马头山以林为主,20m等高线以下则以大田作物为主,种植稻、麦、棉、豆等作物。灌区上游土质属中壤,下游龙尾河一带属轻砂壤土。地下水埋深一般为4~5m,土壤及地下水的pH值属中性,无盐碱化威胁。界荣山、龙尾山等属土质丘陵,表土属中粘壤土,地表5~6m以下为岩层,申溪及吴家沟等沟溪均有岩石露头,马头山陈村以南至马清河边岩石遍布地表。吴家沟等沟溪纵坡较大,下切较深,一般为7~8m,上游宽50~60m,下游宽70~90m,遇暴雨时易暴发洪水,近年来已在各沟、溪上游修建多处小型水库,山洪已基本得到控制,对灌区无威胁。马清河灌区为马清河流域规划的组成部分。根据规划要求,已在兴隆峪上游20km处建大型水库一座,坝顶高程50.2m,正常水位43.0m,兴利库容1.2×108m3,总库容2.3×108m3。马清河灌区拟在该水库下游断面处修建拦河坝式取水枢纽,引取水库水发电尾水进行灌溉。断面处河底高程30m,砂、卵石覆盖层厚2.5m,下为基岩,河道比降1/100,河底宽82m,河面宽120m。水库所供之水水质良好,含沙量极微,水量亦能完全满足灌区用水要求。1.2气象根据当地气象站资料,设计的中等干旱年(相当于1972年)4~11月水面蒸发量(80cm口径蒸发皿)及降水量见表1-1及表1-2。

表1-1设计年蒸发量统计月份4567蒸发量(mm)97.5118.0143.7174.9月份891011蒸发量(mm)196.5144.7101.175.6表1-2设计年降水量统计(mm)日月份4567891017.64.6212.717.418.533.41.97.3492.055.31.210.864.87.92.878.628.582.5919.1103.6112.52.1121.96.4137.52.31412.11.91.91510.0166.04.13.532.81724.5181.3191.6204.312.611.5211.818.5222.110.649.22.53.6231.410.74.52435.47.4256.2261.5271.1281.53.729307.7313.6月计72.9108.5107.339.825.037.3103.51.3种植计划及灌溉经验灌区以种植水稻为主,兼有少量旱作物,各种作物种植比例见表1-3。表1-3作物种植比例作物旱稻中稻双季晚稻棉花种植比例(%)50305020根据该地区灌溉试验站观测资料,土壤空隙率为48%(占土体的%),田间持水率为88%(占空隙%)。设计年(1972)早稻全生育期需水系数=1.0,泡田定额为70m3/亩;棉花计划产量120kg,需水系数k=2.67m3/kg,土壤适宜含水率上限为88%,下限为61.6%(占空隙%),播前灌计划湿润层深为0.4m,播前计划湿润层平均含水率65.3%(占空隙%),播种时计划湿润层土壤实际储水量为102m3/亩。早稻及棉花的基本观测数据如表1-4及表1-5所示;中稻及晚稻的丰产灌溉制度计算见表1-6。表1-4早稻试验基本数据生育阶段复苗分蘖前分蘖后孕穗抽穗乳熟黄熟全生育期起止日期(日/月)25/4~4/55/5~14/515/5~1/62/6~16/617/6~30/61/7~11/712/7~20/725/4~20/7天数101018151411987模比系数(%)78182521138100田间允许水层深(mm)10-30-5010-40-8020-50-9020-50-10020-50-9010-40-50湿润渗透强度(mm/d)1.31.31.31.31.31.31.3表1-5棉花试验基本数据生育阶段幼苗期现蕾期开花结铃期吐絮期全生育期起止日期(日/月)21/4~16/617/6~28/729/7~26/827/8~6/1121/4~6/11模比系数(%下水补给量占作物需水量的(%)10202225计划湿润层深(m)0.4~0.50.5~0.60.6~0.70.7表1-6中稻、双季晚稻设计年丰产灌溉制度中稻双季晚稻灌水次序灌水时间(日/月)灌水定额(/亩)灌水次序灌水时间(日/月)灌水定额(/亩)1(泡田)7/5751(泡田)19/770226/525227/71534/62531/825410/62547/820520/630512/82562/730623/83078/730727/830814/730831/830922/73096/9301029/7251012/9301110/8201119/9301230/920灌溉定额345(/亩)灌溉定额355(/亩)1.4灌区开发的必要性和可行性1.灌区开发的必要性分析(1)从作物需水要求来说,该灌区灌溉面积近12万亩,地形相对平坦,适宜农作物的成长,其种植的作物包括有早稻、中稻、双季稻和棉花,都是相对来说耗水的经济作物,种植比例为50:30:50:20。多年平均蒸发量和降雨量基本持平,现有的自然条件不能满足作物的需水要求。(2)就目前的灌溉与排水条件来说,在灌区有两条河流,但都是流量比较小的河流且分布不均匀,无法满足整个灌区的灌水要求,因此修建灌溉系统十分必要。2.灌区开发的可行性分析就灌区开发的有利条件来说,该灌区位于河流冲击所形成的平原带,其正南方有马清河通过,而在马清河上游有一兴利库容1.2×1380m,总库容2.3×1380m的水库,取水水源方便、水质良好,符合灌溉的基本条件。其次引取水库水发电则利用尾水进行灌溉,既考虑了资源充分利用,又兼顾经济效益。综上所述,该地域修建灌溉系统,实际上必要,技术上可行,同时能实现经济效益、社会效益、生态效益的统一。

2早稻及棉花的灌溉制度计算2.1早稻的灌溉制度计算由已知的气象资料可知,在早稻的全生育期的蒸发量为:所以可得各生育阶段的需水量,继而可得出逐日耗水量,计算结果如表2-1。表2-1逐日耗水量计算表生育期复苗分蘖前分蘖后孕穗抽穗乳熟黄熟全生育期起止日月25/4~4/55/5~14/515/5~1/62/6~16/617/6~30/61/7~11/712/7~20/725/4~20/7天数101018151411987模比系数﹪78182521138100阶段需水量(mm)27.5831.5270.9398.5282.7551.2331.52394.06阶段渗漏量(mm)131323.419.518.214.311.7113.1阶段耗水量(mm)40.5844.5294.33118.02100.9565.5343.22507.16逐日耗水量(mm)4.064.455.247.877.215.964.8注:稻田渗漏量为1mm/d当淹灌水层减去逐日耗水量,加上逐日降雨量后若小于最小田间允许最小水层深度则设计灌水,当大于最大田间允许水层深度则设计排水。水量平衡方程:早稻生育期灌溉制度计算结果见表2-2。表2-2早稻生育期灌溉制度计算表日期生育期设计淹灌水层(mm)逐日耗水量(mm)逐日降雨(mm)淹灌水层变化(mm)灌水量(mm)排水量(mm)月日4242025复苗期10-30-504.0615.942611.882727.8220281.525.262921.23017.145113.08229.022033.428.364226.35分蘖期10-40-804.451.223.0567.926.5728.550.55846.1941.651037.2112.535.25126.437.21332.751428.315分蘖末20-50-905.2448.062516648.821724.568.081862.841957.62052.362147.122210.652.482310.757.942452.72547.462642.22271.138.08283.736.542931.33026.063145.82256140.5862孕穗20-50-1007.8717.450.1131.944.14436.27528.4620.53747.6635839.79931.921024.051146.18301238.311330.44141.924.471546.6301638.7317抽穗20-50-907.2131.521824.311947.1302039.892132.682249.274.672367.462435.4905.652582.79261.577.082769.872862.662955.453048.2471乳熟10-40-505.9642.28236.32330.36424.4518.44612.48736.5230830.56924.61018.641112.6812黄熟湿润4.87.88133.081415103.48164.12.7817181920∑463.97217.32455.65校核:与7月11日淹灌水层基本相符。可得早稻生育期设计灌溉制度,见表2-3。表2-3早稻灌溉制度表灌水次数灌水日期灌水定额mm/亩14月27日2013.325月2日2013.335月15日2516.745月31日2516.756月7日3523.366月11日3020.076月15日3020.086月19日3020.097月5日3523.3107月10日3020.02.2棉花的灌溉制度计算棉花全生育期的需水量为:即其各生育阶段的需水量为:各生育阶段地下水补给量为:由于计划湿润层增加而增加的水量:计划湿润层的最大、最小蓄水量:计划湿润层深度H(m):有效降雨量,用降雨入渗系数α法求取:α的选取按表2-4计:表2-4α取值表次降雨量<5mm5~50mm>50mmα01.0~0.80.7~0.8棉花灌溉制度表见表2-5。表2-4棉花灌溉定额计算表日期生育阶段计划湿润层深4/20幼苗期0.400112.7078.894.30102.004/210.400112.7078.891.800.000.101.01101.094/220.402113.1979.232.100.420.101.01100.604/230.404113.6879.581.400.420.101.01100.114/240.405114.1879.9300.420.101.0199.624/250.407114.6780.2700.420.101.0199.134/260.409115.1780.6200.420.101.0198.644/270.411115.6680.9600.420.101.0198.154/280.412116.1681.311.500.420.101.0197.664/290.414116.6581.6600.420.101.0197.174/300.416117.1482.0000.420.101.0196.685/10.418117.6482.3500.420.101.0196.185/20.419118.1382.6900.420.101.0195.695/30.421118.6383.043.400.420.101.0195.205/40.423119.1283.39200.420.101.0194.715/50.425119.6283.731.200.420.101.0194.225/60.426120.1184.087.94.740.420.101.0198.475/70.428120.6084.4228.517.10.420.101.01115.085/80.430121.1084.7700.420.101.01114.595/90.432121.5985.1200.420.101.01114.105/100.433122.0985.4600.420.101.01113.615/110.435122.5885.812.500.420.101.01113.125/120.437123.0886.156.43.840.420.101.01116.475/130.439123.5786.5000.420.101.01115.985/140.440124.0686.8500.420.101.01115.495/150.442124.5687.1900.420.101.01115.005/160.444125.0587.5463.60.420.101.01118.115/170.446125.5587.8824.514.70.420.101.01125.556.775/180.447126.0488.2300.420.101.01125.065/190.449126.5488.5800.420.101.01124.575/200.451127.0388.9200.420.101.01124.085/210.453127.5289.2700.420.101.01123.595/220.454128.0289.6110.66.360.420.101.01128.021.445/230.456128.5189.9610.76.420.420.101.01128.515.445/240.458129.0190.3100.420.101.01128.025/250.460129.5090.6500.420.101.01127.535/260.461130.0091.0000.420.101.01127.045/270.463130.4991.341.100.420.101.01126.555/280.465130.9891.693.700.420.101.01126.065/290.467131.4892.0400.420.101.01125.575/300.468131.9792.3800.420.101.01125.085/310.470132.4792.7300.420.101.01124.596/10.472132.9693.0700.420.101.01124.106/20.474133.4693.4217.410.440.420.101.01133.460.596/30.475133.9593.771.900.420.101.01132.976/40.477134.4494.1100.420.101.01132.486/50.479134.9494.4600.420.101.01131.986/60.481135.4394.8000.420.101.01131.496/70.482135.9395.1500.420.101.01131.006/80.484136.4295.5000.420.101.01130.516/90.486136.9295.8400.420.101.01130.026/100.488137.4196.1900.420.101.01129.536/110.489137.9096.5300.420.101.01129.046/120.491138.4096.8800.420.101.01128.556/130.493138.8997.2300.420.101.01128.066/140.495139.3997.571.900.420.101.01127.576/150.496139.8897.9200.420.101.01127.086/160.498140.3898.2600.420.101.01126.596/17现蕾期0.500140.8798.6100.420.462.29125.186/180.502141.5499.0800.570.462.29123.926/190.505142.2199.5500.570.462.29122.666/200.507142.88100.0200.570.462.29121.406/210.510143.55100.4900.570.462.29120.146/220.512144.22100.9649.229.520.570.462.29144.224.176/230.514144.90101.4300.570.462.29142.966/240.517145.57101.9035.421.240.570.462.29145.5717.386/250.519146.24102.3700.570.462.29144.316/260.521146.91102.841.500.570.462.29143.046/270.524147.58103.3000.570.462.29141.786/280.526148.25103.7700.570.462.29140.526/290.529148.92104.2400.570.462.29139.266/300.531149.59104.7100.570.462.29138.007/10.533150.26105.1800.570.462.29136.747/20.536150.93105.6500.570.462.29135.487/30.538151.60106.1200.570.462.29134.227/40.540152.27106.5900.570.462.29132.967/50.543152.95107.0600.570.462.29131.707/60.545153.62107.5300.570.462.29130.447/70.548154.29108.0000.570.462.29129.187/80.550154.96108.4700.570.462.29127.927/90.552155.63108.9400.570.462.29126.667/100.555156.30109.4100.570.462.29125.407/110.557156.97109.8800.570.462.29124.147/120.560157.64110.3500.570.462.29122.887/130.562158.31110.8200.570.462.29121.617/140.564158.98111.2900.570.462.29120.357/150.567159.65111.761060.570.462.29125.097/160.569160.32112.234.100.570.462.29123.837/170.571160.99112.7000.570.462.29122.577/180.574161.67113.1700.570.462.29121.317/190.576162.34113.6400.570.462.29120.057/200.579163.01114.1100.570.462.29118.797/210.581163.68114.5700.570.462.29117.537/220.583164.35115.042.500.570.462.29116.277/230.586165.02115.514.500.570.462.29160.01457/240.588165.69115.987.44.440.570.462.29163.197/250.590166.36116.4500.570.462.29161.937/260.593167.03116.9200.570.462.29160.677/270.595167.70117.3900.570.462.29159.417/280.598168.37117.8600.570.462.29158.157/29开花结铃期0.600169.04118.3300.570.582.65156.657/300.603170.02119.017.74.620.830.582.65160.037/310.607170.99119.693.600.830.582.65158.788/10.610171.96120.3700.830.582.65157.548/20.614172.93121.0500.830.582.65156.308/30.617173.90121.7300.830.582.65155.068/40.621174.87122.4100.830.582.65153.818/50.624175.85123.0910.86.480.830.582.65159.058/60.628176.82123.7700.830.582.65157.818/70.631177.79124.4500.830.582.65156.578/80.634178.76125.1300.830.582.65155.328/90.638179.73125.8100.830.582.65154.088/100.641180.70126.4900.830.582.65152.848/110.645181.67127.1700.830.582.65151.608/120.648182.65127.8500.830.582.65150.368/130.652183.62128.5300.830.582.65149.118/140.655184.59129.2100.830.582.65147.878/150.659185.56129.8900.830.582.65146.638/160.662186.53130.5700.830.582.65145.398/170.666187.50131.2500.830.582.65144.148/180.669188.47131.9300.830.582.65142.908/190.672189.45132.611.600.830.582.65141.668/200.676190.42133.2912.67.560.830.582.65147.988/210.679191.39133.9700.830.582.65146.748/220.683192.36134.6500.830.582.65145.498/230.686193.33135.3300.830.582.65144.258/240.690194.30136.0100.830.582.65143.018/250.693195.28136.6900.830.582.65141.778/260.697196.25137.3700.830.582.65140.528/27吐絮期0.700197.22138.0500.830.311.25140.428/280.700197.22138.0500.000.311.25139.488/290.700197.22138.0500.000.311.25138.558/300.700197.22138.0500.000.311.25192.61558/310.700197.22138.0500.000.311.25191.689/10.700197.22138.0500.000.311.25190.749/20.700197.22138.0500.000.311.25189.819/30.700197.22138.057.34.380.000.311.25193.259/40.700197.22138.0500.000.311.25192.329/50.700197.22138.0500.000.311.25191.389/60.700197.22138.0500.000.311.25190.459/70.700197.22138.0500.000.311.25189.529/80.700197.22138.0500.000.311.25188.589/90.700197.22138.0500.000.311.25187.659/100.700197.22138.0500.000.311.25186.719/110.700197.22138.052.100.000.311.25185.789/120.700197.22138.0500.000.311.25184.849/130.700197.22138.052.300.000.311.25183.919/140.700197.22138.0500.000.311.25182.979/150.700197.22138.0500.000.311.25182.049/160.700197.22138.053.500.000.311.25181.119/170.700197.22138.0500.000.311.25180.179/180.700197.22138.0500.000.311.25179.249/190.700197.22138.0500.000.311.25178.309/200.700197.22138.0500.000.311.25177.379/210.700197.22138.0518.511.10.000.311.25187.539/220.700197.22138.053.600.000.311.25186.609/230.700197.22138.0500.000.311.25185.669/240.700197.22138.0500.000.311.25184.739/250.700197.22138.0500.000.311.25183.799/260.700197.22138.0500.000.311.25182.869/270.700197.22138.0500.000.311.25181.939/280.700197.22138.0500.000.311.25180.999/290.700197.22138.0500.000.311.25180.069/300.700197.22138.0500.000.311.25179.1210/10.700197.22138.054.600.000.311.25178.1910/20.700197.22138.0518.511.10.000.311.25188.3510/30.700197.22138.0500.000.311.25187.4210/40.700197.22138.0500.000.311.25186.4810/50.700197.22138.0500.000.311.25185.5510/60.700197.22138.052.800.000.311.25184.6210/70.700197.22138.0500.000.311.25183.6810/80.700197.22138.052.500.000.311.25182.7510/90.700197.22138.0519.111.460.000.311.25193.2710/100.700197.22138.053.600.000.311.25192.3410/110.700197.22138.0500.000.311.25191.4010/120.700197.22138.0500.000.311.25190.4710/130.700197.22138.0500.000.311.25189.5310/140.700197.22138.051.900.000.311.25188.6010/150.700197.22138.0500.000.311.25187.6610/160.700197.22138.0532.819.680.000.311.25197.229.1910/170.700197.22138.0500.000.311.25196.2810/180.700197.22138.0500.000.311.25195.3510/190.700197.22138.0500.000.311.25194.4210/200.700197.22138.0511.56.90.000.311.25197.223.1610/210.700197.22138.0500.000.311.25196.2810/220.700197.22138.0500.000.311.25195.3510/230.700197.22138.0500.000.311.25194.4210/240.700197.22138.0500.000.311.25193.4810/250.700197.22138.056.23.720.000.311.25196.2710/260.700197.22138.0500.000.311.25195.3310/270.700197.22138.0500.000.311.25194.4010/280.700197.22138.0500.000.311.25193.4610/290.700197.22138.0500.000.311.25192.5310/300.700197.22138.0500.000.311.25191.5910/310.700197.22138.0500.000.311.25190.6611/10.700197.22138.0500.000.311.25189.7211/20.700197.22138.0500.000.311.25188.7911/30.700197.22138.0500.000.311.25187.8611/40.700197.22138.0500.000.311.25186.9211/50.700197.22138.0500.000.311.25185.9911/60.700197.22138.0500.000.311.25185.05

3灌水率计算根据所计算得的早稻、棉花及给出的中稻、双季晚稻的灌溉制度以及作物比例分别计算出其灌溉率,各次灌水的灌水率为:计算列入表3-1。表3-1初步灌水率计算表作物种植比例%灌水次数灌水时间(月/日)灌水定额延续时间(d)灌水率/(s·万亩)早稻501(泡田)4月19日70.060.6824月27日13.340.1935月2日13.340.1945月15日16.740.2455月31日16.740.2466月4日23.350.2776月11日20.040.2986月15日20.040.2996月19日20.040.29107月7日20.050.23中稻301(泡田)5月7日75.060.4325月26日25.040.2236月4日25.050.1746月10日25.050.1756月20日30.040.2667月2日30.040.2677月8日30.040.2687月14日30.040.2697月22日30.040.26107月29日25.040.22118月10日20.040.17双季晚稻501(泡田)7月19日70.060.6827月27日15.040.2238月1日25.040.3648月7日20.040.2958月12日25.040.3668月23日30.040.4378月27日30.040.4388月31日30.050.3599月6日30.050.35109月12日30.050.35119月19日30.040.43129月30日20.040.29棉花2017月23日45.070.1528月30日55.070.18将所得灌水率绘在方格纸上得初步灌水率图,如图3-1,后经修正后得最后的灌水率图,如图3-2,选取延续时间较长的最大灌水率值。图3-1初步灌水模数图图3-2修正后灌水模数图取修正后的灌水率为0.41m3/(s*万亩)。

4灌排渠系及渠系建筑物规划布置4.1水源与取水口选择灌区的水源主要是以马清河为灌溉水源。马清河上游,水位较高,河岸坚硬,河槽较稳定,还有一座水库水质良好,含沙量极微,灌区上游土质属中壤,下游龙尾河一带属轻砂壤土。地下水埋深一般为4~5m,土壤及地下水的PH值属中性,无盐碱化威胁。取水口宜取在凹岸中点偏下游处,取水口在这里可利用横向环流作用,使主流接近取水口,加大进流量,有效防止泥沙淤积渠口和进入渠道,避免水直接冲击渠道,有利于渠道的保护。4.2各级渠道与排水沟布置本灌区灌溉渠道分为干、支、斗、农四级固定渠道。本灌区属于小坡度地区。一支布置在整个灌区的西面,与等高线成一定的角度。二支布置在吴家沟和申溪之间,三支布置在小坳与新村连线,四支布置在枯石村与陈留连线,即整个灌区由四条支渠控制。第三支渠灌溉面积适中,可作为典型支渠,该支渠有12条斗渠,斗渠长1800m。每条斗渠有8条农渠,长750m,间距250m。4.3渠系建筑物布置渠系建筑物是指与渠道配套的水闸、涵洞、桥梁、渡槽、倒虹吸、跌水、陡坡等建筑物。1.渠系建筑物的选型与布置原则(1)尽量采用定型设计和装配式建筑物;(2)尽量利用当地材料修建;(3)渠系建筑物的位置应根据渠系平面布置图、渠道纵横断面图及当地情况合理布局;(4)渠系建筑物应满足渠道输水、配水、量水、泄水和防洪等要求,保证渠道正常运行,最大限度地满足作物需水要求;(5)渠系建筑物布置尽可能集中,联合修建,形成枢纽,降低造价,便于管理;(6)布置渠系建筑物应使水流流态稳定,水头损失小。2.主要的渠系建筑物(1)引水建筑物进水闸:在渠道取水处,调节干渠的进水流量,满足灌溉对水位、流量的要求。(2)配水建筑物1)分水闸:布置在各支渠、斗渠和农渠渠首。上级渠道的分水闸就是下级渠道的进水闸。分水闸的作用是控制和调节向下级渠道的配水流量,其结构形式有开敞式和涵洞式两种。2)节制闸:垂直于渠道中心线布置,其作用是控制渠道水位或流量。下列情况需要设置节制闸:①在上级渠水位不能保证下级渠正常引水时,需在上级渠建节制闸抬高水位,保证下级渠引水。②实行轮灌时,在轮灌组分界处需设节制闸。③在重要建筑物或险工渠段前需联合修建节制闸和泄水闸,以防止漫溢,保证建筑物和渠道的安全。3.交叉建筑物常见的交叉建筑物有:隧洞、渡槽、倒虹吸、涵洞、桥梁等。(1)隧洞:当渠道遇到山岗时,或因石质坚硬,或因开挖工程量过大,往往不能采用深挖方渠道,如沿等高线绕行,渠道线路又过长,工程量仍然较大,而且增加了水头损失。在这种情况下,可选择山岗单薄的地方凿洞而过。(2)倒虹吸:渠道穿过河沟、道路时,如果渠道水位高出河沟洪水位,但渠底高程却低于河沟洪水位时;或渠底高程虽高于路面,但净空不能满足交通要求时,就要用压力管道代替渠道,从河沟、道路下面通过,压力管道的轴线向下弯曲,形似倒虹。(3)渡槽:渠道穿过河沟、道路时,如果渠底高于河沟最高洪水位或渠底高于路面的净空大于行驶车辆要求的安全高度时,可架设渡槽;渠道穿越洼地时,如采用高填方渠道工程量太大,也可采用渡槽。(4)涵洞:渠道与道路相交,渠道水位低于路面,而且流量较小时,常在路面下面埋设平直的管道,叫做涵洞。(5)桥梁:渠道与道路相交,渠道水位低于路面,而且流量较大,水面较宽时,要在渠道上修建桥梁,满足交通要求。4.衔接建筑物当渠道经过坡度较大的地段时,为防止渠道冲刷,保持渠道的设计比降,就把渠道分成上、下两段,中间用衔接建筑物联结,常见的衔接建筑物有跌水或陡坡。(1)跌水:水位落差小于3m时,宜建跌水。(2)陡坡:水位落差大于3m时,宜建陡坡。5.泄水建筑物用于排除渠道中余水或入渠洪水。(1)退水闸:布置在较大的干、支、斗渠末端,以排泄渠中余水(防止滋生杂草和蚊虫)。

(2)泄水闸:与节制闸联合修建,保护重要建筑物和险工渠段。6.量水建筑物(1)利用闸、涵、渡槽等量水。在干支渠上量水一般利用这些渠系建筑物量水。(2)利用特设计量水设备量水。如三角堰、梯形堰、巴歇尔量水槽、喷嘴等。一般斗、农渠上可采用特设量水设备。渠系建筑物的布置具体见干渠纵断面附图1.

5水位推算5.1初拟各级渠道比降一般干渠比降为1/10000左右,支渠比降为1/5000左右,斗渠比降为1/2000左右,农渠比降为1/1000左右。5.2选择地面控制点地面控制点即灌溉区域内最难控制的点,可通过比较渠道比降和地面比降来确定控制点在渠道首部,还是在渠道末端。一般通过以下步骤确定控制点位置:若干渠比降≥干渠沿线地面比降,则控制点位于灌区尾部,反之位于灌区首部;若支渠比降≥支渠沿线地面比降,则控制点位于支渠尾部,反之位于支渠首部;若斗渠比降≥斗渠沿线地面比降,则控制点位于斗渠尾部,反之位于斗渠首部;若农渠比降≥农渠沿线地面比降,则控制点位于农渠尾部,反之位于农渠首部,最终确定控制点位置。5.3推算典型支渠渠首设计水位各级渠道入口处的水位是根据灌溉面积上控制点的高程加各种水头损失,自下而上逐级推算出来的。水位公式如下:水里通过渠系建筑物的水头损失如表5-1所示。表5-1渠道建筑物水头损失最小数值表渠别控制面积(万亩)进水闸节制闸渡槽倒虹吸公路桥干渠10~400.1~0.20.10.150.40.05支渠1~60.1~0.20.070.070.30.03斗渠0.3~0.40.05~0.150.050.050.20农渠0.05取第四支渠为典型支渠。1.支渠:,;>,取支渠首为控制点。2.斗渠:,,;<。取斗渠渠尾为控制点。3.农渠:,;>,取农渠渠首为控制点。4.计算支渠渠首设计水位5.4推算干渠设计水位5.5确定引水方式根据渠首设计水位和设计年取水口水位,确定取水方式是无坝取水。

6计算渠道设计流量6.1确定工作制度干支渠续灌,斗、农渠轮灌(各分两组)。6.2计算典型支渠设计流量灌区总面积约为11.5万亩,干渠长为18.005km,各支渠的长度及灌溉面积列入表6-1。表6-1支渠长度及灌溉面积渠别一支二支三支四支合计长度(km)3.9224.1834.1964.516.801灌溉面积(万亩)1.7842.8903.2093.58011.4631.典型支渠(三支渠)及其所属斗、农渠的设计流量(1)计算农渠的设计流量三支渠的田间净流量为:因斗、农渠分两组轮灌,同时工作的斗渠有6条,同时工作的农渠有4条,所以,农渠的田间净流量为:取田间水利用系数,农渠的净流量为:灌区土壤属中粘壤土,查表得相应的土壤透水性参数:。据此可计算农渠每公里输水损失系数:取农渠的计算长度农渠的的设计流量为:(2)计算斗渠的设计流量因一条斗渠内同时工作的农渠有4条,即斗渠的流量为:农渠分两组轮灌,各组要求斗渠供给的净流量相等。但是,第Ⅱ轮灌组距斗渠进水口较远,输水损失水量较多,据此求得的斗渠毛流量较大,因此以第Ⅱ轮灌组的斗渠毛流量作为斗渠的设计流量。斗渠的工作长度为。斗渠每公里输水损失系数为:斗渠的设计流量为:。(3)计算三支渠的设计流量斗渠也是分两组轮灌,以第Ⅱ轮灌组要求的支渠毛流量作为支渠的设计流量。支渠的工作长度取。支渠的净流量为:支渠每公里输水损失系数为:支渠的设计流量为:2.计算三支渠的灌溉水利用系数:3.计算一、二支渠的设计流量(1)计算一、二、四支渠的田间净流量(2)计算一、二、四支渠的设计流量以典型支渠(三支渠)的灌溉水利用系数作为扩大指标,用来计算其他支渠的设计流量。6.3计算干渠设计流量(1)EF段的设计流量(2)CE段的设计流量(3)AC段的设计流量(4)OA段的设计流量5.灌区灌溉水利用系数

7渠道横断面设计7.1干渠各断面设计设计过水断面采用实用经济断面,取,,。拟定偏离系数。计算:。计算宽深比:。计算:。5.6.校核不冲不淤:,清水渠取0.3~0.4;;要求<<。计算结果见表7-1。表7-1干渠各

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