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Shihmen Management Office

Shihmen Management Office

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Irrigation Areas

Operational area

The office’s operational area is located in northwest Taiwan, spanning 3 counties and cities including New Taipei City, Taoyuan City, and Hsinchu County, including Yingge, Taoyuan, Bade, Daxi, Guanyin, Zhongli, Pingzhen, Xinwu, Yangmei and Hukou. The irrigated area of 12 townships and cities includes Xinfeng and Zhubei and was originally planned to be 21,926 hectares, but is actually 12,085 hectares. It stretches from Yingge District and New Taipei City eastwards to Fengshan River, Hsinchu County, in the west. To the south are hills and the Taoyuan Terrace plateau, next to the irrigation area of Taoyuan Management Office, Irrigation Agency in the north.

The picture below shows a map of the office’s irrigation area.

irrigation area
Natural environment

The elevation of the irrigation area ranges from 100m to 240m above sea level, with a slope of roughly 1:80 to 1:120, sloping from southeast to northwest, forming a fan-shaped alluvial hilly area.

The irrigation area forms a natural drainage system, including Nankan River, Xinjie River, Laojie River, Dajue River, Shezi River and other rivers.

Irrigation channel overview

The office’s irrigation area is based on Shimen Canal with lateral canals set up for irrigation according to the topography of the area. If the regional irrigation area is large, additional sub-lateral canals are set up in the lateral canals. Water is distributed from the sub-lateral canals to the rotation irrigation area. Small ditches are set up in the rotation irrigation area to supply water to the fields for rice crop irrigation.

Main facilities include

The main canal tunnel is 4,489m in length; there is one main canal, Shimen Canal which is 27,363m long; 16 lateral canals, with a total length of 77km; 34 sub-lateral canals, with a total length of 121km; small ditches with a total length of 970km; there are 5 main adjustment gates that divert water from the main canal and lateral canals.

Irrigation water source

The water used in this irrigation area is mainly diverted from Shimen Reservoir, which accounts for 48% of the water used. The insufficient water volume is regulated and managed by effective rainfall, weirs, pond storage, pumping stations and groundwater wells.

Currently, there are 228 weirs; 3 pumping stations; 3 underground deep water wells; and 398 retention ponds.

Shimen Reservoir

The main source of agricultural water in the operation area is from Shimen Reservoir, which accounts for 48% of the total. Other supplementary water sources include pond storage, weir interception and diversion, pumping stations, underground wells and effective rainfall, which account for 52%.

River weirs

The main water source for farmland in the office’s irrigation area is Shimen Reservoir, which accounts for 48% of the total, with the remaining 52% dependent on supplementary water sources. In addition, the irrigation area has a special topography and its natural slope of 0.03% is utilizedto build river weirs that intercept surface runoff water from up-stream and part of the field irrigation water that flows into the river, capturing the lost water and reusing it.

The utilization of returned water accounts for about 20% of water demand in the local irrigation area. To this end, river weirs are built on each river to intercept the water for direct irrigation, or directly introduced into lateral and sub-lateral canal storage pools to supplement the shortage of water diverted from Shimen Reservoir and increase the regulating function of the storage pools.

There are 228 river weirs in the jurisdiction, with a maximum water diversion capacity of 4.1m3.

Pond management and use
Description

There were originally more than 3,000 small and large ponds in the irrigation area but after the completion of Shimen Reservoir, the plan was re-considered in 1989 and 460 retention ponds approved. The current status is as mentioned above.

Because the ponds are distributed acrossNew Taipei City, Taoyuan City and Hsinchu County, management is extremely difficult. Disputes arise from time to time over water storage and release, and random reclamation and planting are common. Without improved management, it is insufficient to maintain the safety of the ponds and irrigation function, while at the same time transferring water from Shimen Reservoir to the retention ponds. The office has spent a huge amount of money, contributed by members, to meet the above demands and the water in the ponds cannot be left to anyone for free use. In order to reduce the burden on farmers and ensure fair rights and obligations, in July 1970, at the 2nd session of the 3rd Member Representatives Meeting, the rules for the use of retention ponds was passed by a resolution, in accordance with the Organizational Charter of the Taiwan Provincial Irrigation Association, enhancing operations, management, implementation and collection of water usage fees.

Basis for use

The management office may collect construction usage fees, with the remaining water usage fee collected based on the amount of water remaining in the pond before it is used for irrigation and after irrigation. Water users who use the water body to catch fish are required to pay water usage fees.

Rainfall and Climate

Average annual rainfall is about 2,000mm and average annual temperature 21.8 degrees Celsius, making it suitable for crop growing all year round. Double cropping rice cultivation accounts for about 78% of the cultivated land area.

Irrigation area features

The whole area is fan-shaped with hilly land sloping from south to north with excellent drainage.

Most areas are clay loam and clay, with a few areas sandy loam.

Farmers have small parcels of cultivated land (an average of about 0.5 hectares per person) and densely located farmhouses.

In the farmland rezoning area, all the original three-section residential compounds have been converted into small residential buildings (20 to 30 households).

Many small factories are registered as agricultural product processing factories.

There are many ponds (398).

In addition to factories being densely located in the irrigation area, there is also Zhongli Industrial Zone, Shanzaiding Industrial Zone, Youshi Industrial Zone and Hukou Industrial Zone. The employment rate of rural youth is high and farming has become a sideline.

The entire irrigated area is planted with rice, with no farming of dry crops or mixed crops.

The river flow is short, with a fast flow rate and a low quantity of poor quality water that is seriously polluted.

Farmers in the region (except for a very few) can speak Mandarin, Hoklo and Hakka.

There are many temples, and every village in the irrigation area has at least one Fude temple.

Last Updated:2023/11/04
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