Crop monitoring using unmanned aerial vehicle (UAV) remote sensing is an important technique for improvement of crop yield and quality, reduction of environmental load, and research to elucidate vegetation and the water environment. Based on UAV remote sensing and solar radiation datasets, this study was conducted to investigate applicable and simple models to estimate paddy rice plant length and yield. For three varieties (Koshihikari, Fusaotome, Fusakogane), UAV remote sensing datasets were acquired for three locations (Chiba, Niigata, Saitama). Furthermore, solar radiation datasets of two types were analyzed: photosynthetically active radiation (PAR) and global solar radiation (GSR). Salient conclusions of this study were the following: (1) NDVIpure vegetation (NDVIpv) and Green-NDVI (GNDVI) showed high accuracy and applicability for plant length estimation. (2) For Koshihikari, the average solar radiation of the 20-day period from the heading stage was found to have the highest correlation to yield. For Fusaotome and Fusakogane, the average solar radiation of the 30-day period from the heading stage had the highest correlation to yield. (3) Results of yield estimation model application to other years and locations showed that the RMSE of the PAR-based model was 46.5 g/m². The RMSE of the GSR-based model was 23.1 g/m². The GSR-based model outperformed the PAR-based model. Simple models provided in this study can function as applicable algorithms to estimate the paddy rice plant length and yield using UAV remote sensing and solar radiation.

 The relation between disasters and poverty is getting attention recently. Flood is estimated to increase in some Asian countries due to climate change. Many countries which suffer flood damage also have poverty problems. Therefore, some support measures incorporating both flood and poverty should be adopted but local-scale suggestions remain scarce because both flood and poverty present mutually differing spatial characteristics. This study addresses the issue by conducting a field survey to analyze local-scale poverty mechanisms followed by a flood simulation that incorporates the effects of levees, Field survey results indicate that communities play important roles related to poverty in Bago city, Results show that poor people choose to live in flooded areas because of low land prices. Thereafter, they form strong communities with people who have been living in the area. Poor people in flooded areas tend to have low incentives for education due to their satisfaction with life, which is largely related to comfort of the community. On the other hand, results show that communities have some resilience against flood effects. People mutually cooperate during daily life, and especially so during the flood periods. Flood simulation results show that some areas in Bago city cannot be protected even by constructing levees of a certain height. Therefore, not only tangible measures but also intangible measures such as support for poor people during flood periods are required. Results suggest six support measures for use in flood-prone areas for poor people considering the local flood and poverty situation.

 Storm runoff recession curves in a mountainous catchment have been identified as an inherent property, but it remains unclear whether they are influenced by storm event magnitudes. This paper presented an examination of this influence using a hydrological dataset observed for 14 years in a small forested catchment (Shigaraki study site) in Shiga Prefecture, Japan. For large storm events, almost the entire rainfall increase was allocated to the stormflow, suggesting that the stormflow contribution areas were extended to the entire catchment area. They are called fixed events. Runoff recession curves for them were regarded as an inherent catchment property because the recession curves were smooth with no inflection point. On a double logarithmic chart, a constant linear relation was found between the runoff rate (q) and its temporal change (-dq/dt). Although a similar relation was found for intermediate storm events, the lines were not the same but were parallel to those for fixed events. This result shows that the runoff contribution area for each intermediate storm event was limited to a partial catchment area, but the relation between runoff rate and storage was the same as that for fixed events, suggesting that the stormflow recession curves were produced through the vertical unsaturated flow within the runoff contribution areas. A quicker recession curve was detected for each of the runoff recession curves for some intermediate as well as shower-type events, suggesting a local generation of stormflow, but details of the runoff mechanism were left as a subject for future study.

 Methods to evaluate forest soil mitigation effects on stream runoff are presented in this review paper. After introducing the prevailing orthodoxies derived from infiltration capacity and water holding capacity, we traced development of the methods along with elucidation of hillslope runoff mechanisms. The effects of forest are based upon soil-water retention properties and permeability originating from the distributions of soil pore radius, but two effects were produced from them: a reduction effect of stormflow volume compared with a given storm-event rainfall volume through water absorption in soil, and an attenuative effect decreasing the maximum stormflow rate through equalization of its temporal change. The latter effect was modified by additional flow mechanisms through pipe-like preferential pathways and a weathered bedrock layer under the soil layer. Such soil effects described above, however, might be valid considering the evolution of large pores through biological processes and the evolution of preferential pathways through soil-layer development.

 This article reports the applaud of contribution to Hydrological Research Letters in 2016. No article published in 2011 does not meet the minimum requirement of the number of citations for the Highest Impact Articles. Komori et al. (2012) hold the most downloaded articles second straight year.

 Committee on Project Planning held the RRI Model Active Seminar at Korakuen Campus of Chuo University on 22 December 2017 in order to promote better understanding of RRI model and to spread RRI model to domestic and overseas. Prof. Sayama of Kyoto University who is a developer of RRI model, Dr. Miyamoto and Mr. Nakamura from ICHARM had lectures. We had interesting and exciting discussion at the seminar. 66 people (including 27 students) participated in this seminar.