Thousands Of Rivers Research Articles

Machine learning-enabled calibration of river routing model parameters

Abstract Streamflow prediction of rivers is crucial for making decisions in watershed and inland waterways management. The US Army Corps of Engineers (USACE) uses a river routing model called RAPID to predict water discharges for thousands of rivers in the network for watershed and inland waterways management. However, the calibration of hydrological streamflow parameters in RAPID is time-consuming and requires streamflow measurement data which may not be available for some ungauged locations. In this study, we aim to address the calibration aspect of the RAPID model by exploring machine learning (ML)-based methods to facilitate efficient calibration of hydrological model parameters without the need for streamflow measurements. Various ML models are constructed and compared to learn a relationship between hydrological model parameters and various river parameters, such as length, slope, catchment size, percentage of vegetation, and elevation contours. The studied ML models include Gaussian process regression, Gaussian mixture copula, Random Forest, and XGBoost. This study has shown that ML models that are carefully constructed by considering causal and sensitive input features offer a potential approach that not only obtains calibrated hydrological model parameters with reasonable accuracy but also bypasses the current calibration challenges.

A spatio-temporal analysis of changing trends in rainfall patter: A case study of Kutch District

Changing trends captivate millions of analytical minds. It grabs much when the impact on human lives and properties is involved. The utmost concern is changing weather patterns, which led to a worse impact on the amount and distribution of the precipitation. Essentially, the challenge in several nations is to reach the whole population with adequate water per day. Even a country like India, which has thousands of rivers, streams, lakes, ponds, etc. unable to reach the whole population, as it depends on the uneven event, the Monsoon for its >80% annual rain during monsoon months (June-September). The Nation’s westernmost district, Kutch, which holds the title for the largest area-wise district in India, has been bearing from changing trends in rainfall for a long time. The rainfall distribution within the district is uneven and has experienced contrasting extreme events like drought and flood within consecutive years. The present study attempts to analyse the Spatio-temporal rainfall pattern for 58 years from 1961 to 2018 for the Kutch district using the IMD4 long-term daily gridded (High Spatial Resolution, 0.25° x 0.25°) rainfall dataset. In addition, the Mann-Kendall (MK) test and Sen’s slope method were performed to detect the trends and the magnitude of change over the studied period, respectively. The results indicate high rainfall variability during monsoon months in the north and northwest, while relatively moderate and low in the south and west parts of the district, respectively, and show an upward trend in monsoon rainfall at a 5% significance level in all the Taluka of the Kutch district.

Retention Pool As Alternative For Flood Control Case Study Of Bapertarum Housing, Sumenep Regency

Indonesia is a water country with thousands of rivers and hundreds of deep seas. This causes Indonesia to become a country that is very prone to flooding. But basically, there are several factors that cause this to happen, namely: natural events, drainage damage and environmental degradation caused by human activity itself. Geographically, Bapetarum Housing is an area located in a rainwater catchment area so that it is prone to flood events. High rainfall intensity can cause flood inundation as high as 30 cm. The purpose of this study is to calculate the adequacy of the retention pond to cope with flooding. The procedure for collecting research data begins with analyzing the flood, namely primary and secondary data. Meanwhile, the data analysis techniques used are planning rain analysis, rainfall intensity, flood discharge analysis, retention pond capacity. The retention pond capacity is sufficient because the dimensions of the retention pond are larger than the volume of the retention pond capacity when the flood is 6750m3>6447m3. The retention pond is planned in the downstream area of the residential river with a pool area of 50 x 40 meters and a depth of 4.5 m. The bottom condition of the pond is saturated because it is always inundated with water, the infiltration rate is constant (fc). The constant infiltration for clayey soil type is 0.5 m/day, the infiltration volume rate that occurs at the bottom of the pond is 179 m3/hour, the volume is below the threshold 8283.21 m3, infiltration time is 46 hours.

四川丘陵区水库浮游植物群落结构与蓝藻水华风险——基于优势种生态位与种间联结研究

为了解四川丘陵区中小型水库浮游植物群落结构周年变化，掌握其演替规律并预测其发展方向，于2016年-2017年分季节对该地区10个典型水库进行了周年研究。结果显示：共检出浮游植物9门104属188种，其中优势种4门16属16种，以湖泊假鱼腥藻（Pseudanabaena linmnetica）优势度指数为最高；蓝藻密度在各季节、各水库中均占据优势，尤其是夏季。优势种生态位宽度和生态位重叠度在存在明显的季节差异性，并受到水温、营养条件等环境因子的显著影响；优势种可分为3个类别，竞争力相对较强的7个种中有5种蓝藻；全年发展性最强的种类也多为蓝藻，特别是湖泊假鱼腥藻等具有产毒潜力的种类，其优势度存在进一步扩大的风险。种间联结性检验结果显示，群落种间大致表现出净的正联结，优势种种对间正负关联比大于1，该类水库群落结构较为稳定且存在正向演替的趋势，可能会导致夏季间断性产毒蓝藻水华的风险。研究结果可为四川丘陵区中小型水库浮游植物群落演替研究以及蓝藻水华预警提供基础资料。;Sichuan is known as a province with thousands of rivers and numerous reservoirs which play an important role in production and life. There is a general problem of pollution in small and medium-sized reservoirs in this area, which may affect the structure, function and utilization of aquatic ecosystem. Aiming to explore the annual changes and succession rules of phytoplankton community structure in small and medium-sized reservoirs in hilly regions of Sichuan Province and to predict its development direction, this study conducts an annual survey on 10 typical reservoirs in specific regions in different seasons from 2016 to 2017. The survey identifies a total of 188 species of phytoplankton in 104 genera of 9 phyla, including 16 species (9 species are cyanobacteria) of 16 genera of 4 phyla which are identified as dominant species. In particular, the dominance index of Pseudoanabaena linmnetica is the highest, and the density of cyanobacteria is dominant in all seasons and reservoirs, especially in summer. Furthermore, the improved Levins formula and Petraitis index are applied to determine the niche metrics of the phytoplankton dominant species. The results show that the niche breadth and niche overlap of each dominant species vary seasonally and are significantly affected by water temperature and nutrient. Based on their niche breadth in different seasons, the dominant species are classified into three categories, two of which are relatively competitive. These two categories include 7 species, of which there are 5 species of cyanobacteria, including P. linmnetica. The dominant species in four seasons are mostly in a state of developing, and the most promising species throughout the year are mainly cyanobacteria. In particular, species with the potential to produce toxins such as P. linmnetica have the risk of further expansion of their dominance. The results of interspecific association show a positive correlation among the community species throughout the year, indicating that the community structure in these reservoirs is relatively stable and there is a positive succession trend. In such a trend, intermittent toxic cyanobacteria bloom which affects the quality and function of water may occur in these reservoirs in summer, especially in reservoirs with simple dominant species composition.This paper provides research background for the study of phytoplankton community succession and the early warning of cyanobacteria blooms in small and medium-sized reservoirs in hilly regions of Sichuan Province. To prevent possible filamentous cyanobacteria bloom outbreak, water quality of the reservoirs should be effectively managed and immediately repaired under the dual promotion of high nutritional level and global warming.

Impact of Bridge Construction for Improved Livelihood in Rural Area

Nepal has thousands of rivers flowing over its terrain. It needs many bridges for smooth transportation. In this background, this study highlights impact of road bridges like infrastructures on rural livelihood and importance of the local participation in such infrastructure development programme. The study area as the Zone of Influence of ChirdiKhola is ward no. 7 and 10 of Phalebas Municipality which has 1026 households and 4423 populations. Household survey, focus group discussion, key informant interview, observation techniques were used for collecting primary data whereas secondary data were generated from district profile and table review. This study reveals that the bridge has directly or indirectly played crucial role in increasing the freight volume, decreasing the freight cost, increase in number of peoples seeking health facilities through health centers. Local peoples participated to identify the need of bridge and cooperated during the construction of bridge for effective implementation. Motorable Bridge plays vital role in social upliftment and generating the new ideas of income generations. This study also put some light on how Motorable Bridges are constructed in local levels through different programmes, Departments of Nepal Government and the role of District Development Committees in Motorable Bridge projects.

Population decline in the endemic Atlantic salmon (Salmo salar) in Kapisillit River, Greenland

AbstractAtlantic salmon, Salmo salar L., is found throughout the North Atlantic, with thousands of rivers having spawning populations. In Greenland, spawning is limited to one river in West Greenland, the Kapisillit River (64˚N), and the salmon are limited to the lower few kilometres of the system. Using mark–recapture, it was estimated the parr population was 5,953 individuals, and that the population size has declined by 52% since 1959. In spite of this decline, parr density remains high, being between 0.26 and 0.62 parr/m2. Using a historical age‐length key, an estimated minimum of 635 smolt will have descended to the sea in 2017. These will be caught in a fishery currently subject to no regulatory measures and fishing remains the most likely driver of the population decline. The genetically distinct population is endemic to Greenland, and managers should implement measures to conserve this genetic integrity and local biodiversity.