水是哈尼梯田得以持续存在的关键资源。为适应大坡度山地环境，合理利用水资源，避免用水纠纷，哈尼族创造并保持了独特的梯田“分水木刻”管理体系。文章以元阳县垭口大沟的分水木刻体系为研究对象，在实地调查和访谈基础上，总结了沟渠的开挖、沟长的推选方式和职责，绘制了“分水木”的空间分布及其水源关系图，量化了“分水木”的数量及其水量的关系。结果表明：1）垭口大沟的日常管理由村民经过一定的程序选举出来的沟长负责，沟长每年能获得1326-1770kg刚刚收割的稻谷作为劳动补偿，相当于耕种3-4亩梯田的年收成，可见沟长的管理收益较高；2）垭口大沟的分水木刻体系一共包括16根分水木，其中有12根为2个分水口的分水木，有1根为4个分水口，其余3根均为3个分水口；3）空间分布上，受微地形起伏较大影响,分水木在垭口大沟下段比较密集且分布不均匀；4）分水木的长度最长为254cm，最短为86cm，平均为141cm，分水木所在沟渠的流速平均为39.44 cm?s-1，水量最大、最小和平均值分别为387.50cm3?s-1、12.50cm3?s-1和168.75cm3?s-1，可见地势较平的地方分水木较长，流速较慢，流量则与水深、流速和地形有关。

Water resource is a key to the stability of the Hani Rice Terraces. To adapt the high slope of mountainous environment,utilize water resource rationally,avoid disputes of water use,the Hani people created and maintained a unique woodcarving allocating management system of irrigating water (WAMSIW)during the rice farming of terraced fields. We take the WAMSIW of Yakou Ditch in Yuanyang County as the object,based on field investigations and interviews,sum up the ditch excavation,the electing way of ditch leaders and their responsibilities,and draw the spatial distribution of the water-allocating woods,quantify the number of water-allocating woods and their relationships. The results are as follows: ① The director of the ditch,who is elected by a certain way of villagers,should manage the Yakou Ditch. He can get 1326kg to 1 770 kg wet rice just harvested from rice terraces as the labor compensation to manage the Yakou Ditch. It is equivalent to the rice harvest of 3 to 4mu terraced fields which shows a good income of ditch leader. ② There are 16 water-allocating woods on the Yakou Ditch,among which 12 woods have 2 carving-gates,1 wood has 4 carving-gates and the other 3 woods have 3 carving-gates. ③ In the spatial distribution,impacted by the micro-topography,the water-allocating wood is mainly distributed in the lower part of Yakou Ditch. ④ About the length of water-allocating woods,the longest is 254 cm,the shortest is 86cm and the average is 141 cm. The speed of water flow is 39.44 cm/s,the maximum,minimum and average water flow are 387.50,12.50 and 168.75 cm3 /s respectively. If the terrain is flat,the water-allocating wood’s length is longer,and the water speed is slower,which indicate the water flow is impacted by water depth,flow speed and topography.