History
The development of water resources in Japan has historically progressed through the use of water for rice cultivation. Especially during the Edo period, the development of agricultural water facilities advanced significantly, and by the early Meiji period, almost all river flows available with the technology of the time (drought flows) had been fully utilized for agricultural purposes. In April 1896, the River Law (the so-called “Old River Law”) was enacted, replacing customary water management practices with modern river management and river works concepts. Furthermore, in July 1964, the current River Law was comprehensively revised. Agricultural water rights, including those established before the River Law (customary water rights), were granted legal protection under the River Law.
Why river consultation?
Agricultural water, compared to domestic and industrial water, has the following characteristics, making it difficult to assess the required water volume and functionality, often leading to prolonged river consultations:
- Most of the water taken in is discharged downstream and can be reused.
- The amount of water needed varies depending on the type and variety of crops, and changes according to their growth stages, weather conditions, soil conditions, etc.
- Customary water rights, formed over a long history, serve as the foundation, and it functions as a regional water source in rural communities.
- Practical water use must be coordinated integrally across the entire region.
- It plays a crucial role in the overall water cycle of the river basin, such as recharging groundwater and stabilizing river flow.
Consultations topics
When a project involves constructing or renovating agricultural water facilities such as dams or diversion weirs and storing or drawing water from designated rivers under the River Law, the project implementer (water user) must obtain permission from the river administrator under the provisions of the River Law. The series of procedures to obtain this permission is commonly referred to as “river consultation.” (If the Minister of Agriculture, Forestry, and Fisheries or other officials obtain this permission, the consultation is deemed to have been completed.)
The main consultation topics required for land improvement projects are as follows:
- Matters related to the use of water, such as storage and intake (River Law, Article 23)
- Matters related to the occupancy of land within the river area (River Law, Article 24)
- Matters related to the construction of new water facilities, such as dams and diversion weirs, within the river area (River Law, Article 26, Paragraph 1)
Relevant laws
- River Law, Article 23 (Permission for the Occupation of Flowing Water)
Those who wish to occupy the flowing water of a river must obtain permission from the river administrator as specified by the Construction Ministry Ordinance. - River Law, Article 24 (Permission for the Occupation of Land)
Those who wish to occupy land within the river area (excluding land managed under the authority of the river administrator, hereafter referred to in the next article) must obtain permission from the river administrator as specified by the Construction Ministry Ordinance. - River Law, Article 26 (Permission for New Construction of Structures, etc.)
Those who wish to construct, renovate, or remove structures on land within the river area must obtain permission from the river administrator as specified by the Construction Ministry Ordinance.
Content for river consultations
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- Locations Covered:
The target locations include Class A rivers, Class B rivers, and quasi-classified rivers, which are legal rivers. - Actions Covered:
The actions covered include storage, intake, and other activities involving the flow of rivers associated with the construction or renovation of agricultural water facilities as part of a land improvement project. - Applicant for Water Rights and Granting Authority:
The applicant for water rights is generally the project implementer, although it is typically the water user. The granting authority varies depending on the river classification, the amount of water taken, and the size of the irrigated area (refer to Table 1).
- Locations Covered:
Steps for river consultation
The applicant submits an application with the content specified by the law to the granting authority to obtain permission. Once granted, the water rights receive legal protection, leading to a strict review process. Therefore, it is common to conduct preliminary consultations with the regional office of the Ministry of Construction or the river department of the prefectural government before submitting the application.
Investigation for River Consultation:
The application form must prove the appropriateness of the water usage plan, ensure it does not infringe on the rights of other river users, and obtain the river administrator’s consent regarding the safety of the agricultural water facilities and the impact on flood control. This requires a wide range of investigations, including hydrometeorology, water use in fields (farming), water balance, water quality, and geology. It requires a lot of time and expense, so it is important to utilize as much data as possible from the surveys conducted during the planning and detailed design of the land improvement project, conduct preliminary consultations with the river administrator at key points, and record the agreed items in the minutes to avoid setbacks.
Challenges in River Consultations
- Calculation of Agricultural Water Use:
Agricultural water use involves a highly complex water cycle, and there are cases where the water cycle and the amount of water necessary for crop growth cannot be accurately reflected when formulating the water use plan for a land improvement project. As a result, it often takes time to obtain the river administrator’s consent regarding the calculated water use, which requires further consideration from the agricultural engineering side. - Evaluation of the Function of Agricultural Water as Regional Water:
The River Law clearly describes “irrigation,” but it does not evaluate the functions of irrigation water as regional water, such as landscape maintenance, groundwater recharge, and snowmelt mitigation. However, in recent years, there have been demands from not only farmers but also the entire region to establish and implement projects that consider or focus on these functions, indicating the need to specifically evaluate the water rights related to agricultural water’s non-irrigation functions.
In addition, there are many challenges derived from the characteristics of agricultural water, which need to be addressed through the wisdom and technology of agricultural engineering.
