|
|
Hokkaido University Collection of Scholarly and Academic Papers >
Theses >
博士 （環境科学） >
Role of treated wastewater in mitigating urbanization impacts and maintaining regulatory ecosystem services
|
Files in This Item:
|
|
|
Related Items in HUSCAP:
|
| Title: | Role of treated wastewater in mitigating urbanization impacts and maintaining regulatory ecosystem services |
| Other Titles: | 都市化の影響を緩和し調整生態系サービスを維持する上での処理水の役割 |
| Authors: | Ramaiah, Manish1 Browse this author |
| Authors(alt): | ラマイア, マニシュ1 |
| Issue Date: | 25-Mar-2021 |
| Publisher: | Hokkaido University |
| Abstract: | Rapid urbanization -often unplanned- has been disrupting the environmental settings leading to degradation of resources and energy, environment pollution, elevated land surface temperature (LST) leading to urban heat island (UHI) effect and summer heat waves. In this regard creation, and sustenance urban green spaces (UGS) can effectively reduce these impacts. In this regard, use of treated wastewater available year-round in the cities can be advantageous from climate change mitigation, urban sustainability, carbon storage, and sequestration perspectives as well as from improving the regulatory ecosystem services which harmonize microclimate features. Thus, the relationship between urban landscape patterns and microclimate needs to be sufficiently understood to make urban living ecologically, economically, and ergonomically acceptable. With this background, the present study aimed (a) to address the adverse effects of UHI and elevated LST resulting from land use land cover (LULC) alterations along with the role of UGS in regulating microclimate; (b) to estimate water requirements of UGS during the non-rainy months, its carbon biomass and sequestration potential and (c) to evaluate whether treated wastewater is a dependable alternative for maintaining UGS as a measure to mitigate the adverse impacts of urbanization as well as to reduce groundwater extraction. Two traditional cities in India, experiencing different climatic features, were chosen for this study. Panaji city (Koppen classification: Am) situated on the west coast of India receives over 2,750 mm rainfall and Tumkur city (Koppen classification: BSh/Aw) located in interior region receives around 600 mm rainfall. Both cities are proposed to be developed as smart cities. The methods followed included the analyses of satellite imageries for delineating land cover changes and characterization of the 2019 spectral indices of both cities for understanding the LST difference among other microclimate features. Primary (satellite imageries, field survey-based data, and inputs from key-informant survey questionnaires) and secondary (websites, reports in public domain) data were used to address the above stated objectives. By following the standard methods, the monthly evapotranspiration rates were also derived for both these cities for calculating the UGS water requirement. The calculation of water requirements and carbon stocks and sequestration rates of trees, hedge-plans as well as grass-cover was carried out by following standard methods. While the LST varied within 38-42℃ range in Panaji with a substantial water spread area, it remained quite high in the 42-48℃ range in Tumkur (a much larger but highly water scarce city). The average daily water requirements of 34 different tree species, hedge-plants m-2 and grass-cover m-2 were calculated following standard methods. The larger the canopy/crown area, higher the volume of water required. With the canopy area ranging from 4.491 m2 to 593.66 m2, the daily water requirement ranged respectively from 3.05 Ld-1 to 369.43 Ld-1 averaging 23.87 Ld-1 tree-1. Similarly, for hedge plants the daily requirement was 6.77 Lm-2, and for grass-cover(=lawns), 4.57 Lm-2. Using this information, the water requirements for the entire UGS in Panaji and Tumkur were estimated. The UGS of 1.86 km2 in Panaji city requires 6.24 million liters daily. This volume is under 50% of the of 14 MLD total treated wastewater (=recycled water which is environmentally safe) produced and available year-round in Panaji. Currently, over 99% of this treated wastewater is drained into a polluted creek. Notwithstanding the wide variance between 34 different tree species (covering 4012 individual trees), the weighted mean of CO2 sequestered per tree averaged 55 kg y-1. For 23 tree species the Carbon Sequestration Rates (CSR) estimated in this study are first reports. These rates are well within the ranges reported for many tropical species. With a view of showcasing the possibility of improved regulatory ecosystem services, an option to use the treated wastewater for watering the entire UGS in Panaji was examined. From the UGS regulatory ecosystem services viewpoint, numerous ecological and economic advantages as well as some of the UN sustainable development goals met with the use of treated wastewater are highlighted. Ample reduction in groundwater extraction, compensation of evapotranspiration losses, enhanced thermal comforts, greater elimination of water-stress and additional employment opportunities are some of the ecosystem services that can be improved by using treated wastewater for sustainable UGS in Panaji or, many other cities. |
| Conffering University: | 北海道大学 |
| Degree Report Number: | 甲第14331号 |
| Degree Level: | 博士 |
| Degree Discipline: | 環境科学 |
| Examination Committee Members: | (主査) 教授 沖野 龍文, 教授 渡邉 悌二, 准教授 藤井 賢彦, 助教 Ram Avtar, 特任准教授 藏崎 正明, 主任研究員 Pankaj Kumar（地球環境研究戦略機関）, 研究員 Sohail Ahmad（グラスゴー大学） |
| Degree Affiliation: | 環境科学院（環境起学専攻） |
| Type: | theses (doctoral) |
| URI: | http://hdl.handle.net/2115/88938 |
| Appears in Collections: | 学位論文 (Theses) > 博士 （環境科学）
課程博士 (Doctorate by way of Advanced Course) > 環境科学院(Graduate School of Environmental Science)
|
|
