Nutrient Transport and Change Driven by Sub-surface Flow in Alternate Bar Reach

AbstractThe landscape of a river sandbar is composed of several elements, including vegetation, bare areas, side-pools and so on. For sandy river management, it is necessary to determine the contributing factors for the ecosystem functions of alternate bar segments. In recent years, it has been reported that sandbars have a water purification function involving denitrification driven by sub-surface flow, but the details are still unknown. The objective of this study was to develop a model that could be used to examine how the nitrogen is trapped and retained by several elements of a sandbar in an alternate bar reach. We also developed a framework to analyze the temporal change in the denitrification by using a numerical simulation, aerial photos, and a water quality information system. The numerical simulation was performed under the discharge and morphological conditions of the Yahagi River in the Chubu region of Japan. The main results of this study are that the temporal change in the denitrification ecosystem function in a sandbar reach can be quantified using the proposed model and the denitrification activity has increased over the past 40 years. In addition, it was clearly shown that differences in the vegetation distribution and sandbar shape affect the nitrogen dynamics. Thus, the numerical simulation has made it possible to determine the most effective vegetation patterns to maximize the ecosystem function in a sandbar

Numerical Simulation of Primary Production of Periphyton in a Sand River

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Assessment Framework of Eco-Compatible Management of River Basin Complex around a Bay

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Modelling of River Flow and Sediment Load Based on the Hydrological Behavior Model in Yahagi River Basin, Japan

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Flux Network Modeling of Water and Materials In River Basin Complex For Assessment In Eco-Compatible Management

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Quasi-Solitons in Dissipative Systems and Exactly Solvable Lattice Models

A system of first-order differential-difference equations with time lag describes the formation of density waves, called as quasi-solitons for dissipative systems in this paper. For co-moving density waves, the system reduces to some exactly solvable lattice models. We construct a shock-wave solution as well as one-quasi-soliton solution, and argue that there are pseudo-conserved quantities which characterize the formation of the co-moving waves. The simplest non-trivial one is given to discuss the presence of a cascade phenomena in relaxation process toward the pattern formation.Comment: REVTeX, 4 pages, 1 figur

Ecosystem and Fishery of Manila Clam (Ruditapes philippinarum) in Ise-Bay Related to Eco-Compatible Management of Its River Basin Complex

AbstractIse bay, Japan, is located at the river mouth of 10 class-A rivers, and its environment is closely related to management of their river basin complex (RBC). We developed a model to describe the ecosystem of RBC by developing three tool boxes: TB1 to describe the water/material flux network, TB2 to describe ecosystem mechanism in various categories of landscapes, and TB3 to standardize ecosystem services received at local sites and integrate them throughout RBC. Ecosystem has a function to change the fluxes, which is evaluated by TB2, and such flux change can be fed back to the flux networks in TB1. The outputs of the fluxes from the RBC are inputs for currents of water with various qualities to the bay, which can be computed by bay-dynamics modeling. Then it provides various fluxes from the bay interior to landscapes located along coastal zone, and it supports ecosystem there. Fishery is a kind of ecosystem service there. We focused on bivalve, Manila clam (Ruditapes philippinarum) because it uses various landscapes in a bay through its life cycle and it provides fishery activity as ecosystem service. We have developed TB1 and TB2 also in bay area successfully. Then, we evaluate the transition of quality of environments of RBC including Ise bay from the past to the present by using TB1-TB3 for river basin and bay area. Furthermore, we forecast the future situation and then we discuss how we can improve it through various combinations of measures and policies in the RBC as well as in the bay

Development of a Hierarchy-Integrated Simulation Code for Toroidal Helical Plasmas, TASK3D

The present status of the development of a hierarchy-integrated simulation code for toroidal helical plasmas, TASK3D, is reported. TASK3D is developed by extending the integrated modeling code for tokamak plasmas, Transport Analyzing System for tokamaK (TASK) [A. Fukuyama et al., Proc. of 20th IAEA Fusion Energy Conf. (Villamoura, Portugal, 2004) IAEA-CSP-25/CD/TH/P2-3]. In order to extend TASK to be applicable for threedimensional configurations, a new module for the radial electric field in general toroidal configurations has been developed and implemented. As a first test for this implementation, numerical simulations for the time evolution of temperature and electric field are conducted on the basis of an LHD experimental result, by a successful combination of a diffusive transport module and the implemented electric field module

Random regression for modeling soybean plant response to irrigation changes using time-series multispectral data

Plant response to drought is an important yield-related trait under abiotic stress, but the method for measuring and modeling plant responses in a time series has not been fully established. The objective of this study was to develop a method to measure and model plant response to irrigation changes using time-series multispectral (MS) data. We evaluated 178 soybean (Glycine max (L.) Merr.) accessions under three irrigation treatments at the Arid Land Research Center, Tottori University, Japan in 2019, 2020 and 2021. The irrigation treatments included W5: watering for 5 d followed by no watering 5 d, W10: watering for 10 d followed by no watering 10 d, D10: no watering for 10 d followed by watering 10 d, and D: no watering. To capture the plant responses to irrigation changes, time-series MS data were collected by unmanned aerial vehicle during the irrigation/non-irrigation switch of each irrigation treatment. We built a random regression model (RRM) for each of combination of treatment by year using the time-series MS data. To test the accuracy of the information captured by RRM, we evaluated the coefficient of variation (CV) of fresh shoot weight of all accessions under a total of nine different drought conditions as an indicator of plant’s stability under drought stresses. We built a genomic prediction model (MTRRM model) using the genetic random regression coefficients of RRM as secondary traits and evaluated the accuracy of each model for predicting CV. In 2020 and 2021,the mean prediction accuracies of MTRRM models built in the changing irrigation treatments (r = 0.44 and 0.49, respectively) were higher than that in the continuous drought treatment (r = 0.34 and 0.44, respectively) in the same year. When the CV was predicted using the MTRRM model across 2020 and 2021 in the changing irrigation treatment, the mean prediction accuracy (r = 0.46) was 42% higher than that of the simple genomic prediction model (r =0.32). The results suggest that this RRM method using the time-series MS data can effectively capture the genetic variation of plant response to drought