『保健医療科学』 2022 第71巻 第3号 p.241-253（2022年8月）
特集：人口減少社会における持続可能な水供給システムとまちづくり＜総説＞
小規模集落が経営する水供給システムの維持管理作業の支援ニーズと展望
増田貴則 1)，堤晴彩 2)
1)国立保健医療科学院統括研究官 2)鳥取大学地域価値創造研究教育機構
Needs and prospects for supporting maintenance works for water supply systems operated by small communities
MASUDA Takanori 1), TSUTSUMI Harusa 2)
1) Research Managing Director, National Institute of Public Health
2) Platform for Community-based Research and Education, Tottori University
抄録
水道法の規制対象外とされる計画給水人口が100人以下の小規模な水道が全国に多数存在している. これらは集落の住民自らが施設等の管理運営を行なっているが，高齢化や人口減少の進展，施設の老朽化等により，施設等の維持が困難になりつつあると懸念されている.これらのことを踏まえて筆者らは，水供給施設の持続可能な維持管理の在り方の一つの道筋として，行政やNPO法人等の集落外 からの協力による維持管理を提案し，水供給施設の実態を把握するとともに，集落外からの維持管理による支援方策の実現可能性について検討してきた.
西日本の1府11県の小規模水道を対象とし，質問紙調査を実施した結果，地下水に次いで表流水が多く利用されていることがわかったが，塩素消毒なしで表流水を利用している集落も多く，衛生安全性の面から懸念が残った.また，約66%の集落で水が使用できなくなるようなトラブルがかなりの頻度で発生しており，給水の安定性といった面からも脆弱さが懸念される.施設の維持管理作業において負担感が大きい項目は，取水設備の点検・清掃，ろ過池作業，作業場までの移動といった日常時の維持管理作業に加え，停電・断水時や水圧低下時の対応など非常時の対応についても負担の重い作業であることがわかった.
集落外との連携状況とその支援の利用意向を把握するために，追加で質問紙調査を行った結果，集落外の団体と連携したことのない集落は約8割であった. また同調査にて，8つの架空の支援策を紹介し，それらの支援策が集落外の団体から有償あるいは無償にて提供される場合に利用したいかを尋ねた結果，いずれの場合も一定数の集落が利用したい意向を持っていることがわかった. 加えて，集落外の外部団体からの支援を利用することへの抵抗感が高いわけではないことも確認できた.
少数ではあるが地方自治体の中には積極的な支援を行っているケースやNPO団体を活用しているケースがあることがわかった.国が最近創設した特定地域づくり事業共同組合制度は，人口急減地域の小規模水道の作業を支援する枠組みとなる可能性がある. 今後は，支援の可能性をもつ団体に対して意向を調査すること，ならびに活用できそうな国の支援制度等を併せて検討していくなどにより，外部団体の協力によって小規模な水供給施設を維持するための，その実現可能性を高めていく必要があると考えられる.
キーワード: 人口減少，小規模水道，小規模水供給システム，維持管理，民間支援
Abstract
There are many small-scale water supply systems situated throughout Japan that are not regulated by the Water Supply Act. Although these facilities are managed and operated by the residents of the communities themselves, there are concerns that the maintenance of these facilities is becoming increasingly difficult due to an aging and declining population, aging facilities, and other factors. Based on these considerations, the authors have been studying the actual status of such water supply facilities, proposing maintenance and management with cooperation from outside the community, such as the government and NPOs, as one way to ensure the sustainable maintenance and management of the water supply facilities, and examining the feasibility of support measures for such maintenance and management.
A questionnaire survey of small-scale water systems in 12 prefectures in western Japan revealed that there are many villages that use surface water without chlorine disinfection, raising concerns regarding sanitation and safety. In addition, problems such as water outages occurred quite frequently in roughly 66% of these villages, raising concerns about the fragility of the water supply in terms of stability. In addition to normal maintenance and management tasks such as inspections and cleaning of water intake facilities and filtration ponds, and transportation to and from work sites, the survey also found that emergency response tasks such as dealing with power outages, water outages, and low water pressure are also burdensome tasks.
An additional questionnaire survey was conducted to ascertain the status of cooperation with organizations outside the community and the willingness to use such support, which found that roughly 80% of these communities had never cooperated with organizations outside of the community. The same survey also asked respondents whether they would be willing to use eight imaginary support measures, if they were provided by an organization outside the village for a fee or free of charge and found that a certain number of respondents were willing to use these measures, in all cases. In addition, it was also confirmed that there was not a high level of resistance to receiving support from outside organizations.
We found that a small number of local governments are actively providing support for small-scale water systems or utilizing NPO organizations in some cases. A recently established program by the Japanese government could provide a framework for supporting the maintenance and management of small-scale water- works in areas with rapidly declining populations. In the future, it will be necessary to survey organizations that have the potential to provide support, and to examine possible government support programs, in order to increase the feasibility of maintaining small-scale water supply facilities with the cooperation of outside organizations.
keywords: population decrease, small water supply system, maintenance and management, cooperation from outside the community
