Abstract. Kirchner (2016a) demonstrated that aggregation errors due to spatial heterogeneity, represented by two homogeneous subcatchments, could cause severe underestimation of the mean transit times (MTTs) water travelling through catchments when simple lumped parameter models were applied interpret seasonal tracer cycle data. Here we examine effects such on MTTs and young fractions estimated using tritium concentrations in two-part hydrological systems. We find derived from streamflow are...

Abstract During the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident on March 11, 2011, radionuclides such as tritium were released into environment across Japan, obscuring natural background signal of in precipitation. This anthropogenic component was rapidly washed out by precipitation according to measurements Japan. However, impact tritium-based estimation water system transit times and other prefectures Japan remains uncertain. For first time, from FDNPP together with simulated an...

Following the accident at Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011, large quantities of radioactive materials were released into atmosphere and ocean. Since FDNPP nuclear accident, Tokyo Electric Company (TEPCO) operators have been implementing measures to reduce groundwater inflow damaged reactor buildings while pumping water cool the nuclear reactors fuel debris. The resulting huge volume began discharge ocean from August 2023, after being treated by an Advanced...

Abstract. Here we present a general approach of calibrating transient transport models to tritium concentrations in river waters developed for the MT3DMS/MODFLOW model western Lake Taupo catchment, New Zealand. Tritium has known pulse-shaped input groundwater systems due bomb early 1960s and, with its radioactive half-life 12.32 yr, allows determination age. In model, (measured rainfall) passes through system, and simulated are matched measured stream outlets Waihaha, Whanganui, Whareroa,...

Abstract. In this study, we demonstrate the application of tritium in precipitation and baseflow to estimate groundwater transit times storage volumes Hokkaido, Japan. To establish long-term history concentration Japanese precipitation, used data from global network isotopes local studies The record developed for Tokyo area was scaled Hokkaido using values based on wine grown at Hokkaido. Then, concentrations measured with high accuracy river water Japan, were compared mean (MTTs). A total...

Abstract. The purpose of this study is to simulate tritium concentrations and groundwater transit times in river water with particle-tracking (MODPATH) compare them solute transport (MT3DMS) simulations. Tritium measurements are valuable for the calibration models as well understanding watershed storage dynamics. In a previous study, we simulated western Lake Taupo catchment (WLTC) using MODFLOW-MT3DMS model (Gusyev et al., 2013). was calibrated measured at baseflows Waihaha, Whanganui,...

This flood hazard study is the first step towards linking global and local scales of risk assessment under International Flood Initiative ( IFI ) Flagship Project. To simulate river discharges, we utilised a 600‐arcsec grid block‐wise TOP BTOP model to represent scale constructed 15‐arcsec for Rhine River basin. Both models showed similar statistical performances with observed daily flows, especially 1993 1995 floods. For both scales, calculated peak discharges using Gumbel distribution...

The standardized precipitation index (SPI) has been used to monitor and analyze meteorological droughts using long-term monthly from national hydrological services on multiple timescales. Instead of evaluating climatic impacts with separately-computed SPI for present future climates, we introduced the comparative (cSPI) computed target (future) datasets basis a reference (present) dataset. cSPI approach evaluates change in one dataset different periods common period. Using 12-month cSPI,...

Abstract. Nitrogen and phosphorus concentrations in Chinese river catchments are contributed by agricultural non-point industrial point sources causing deterioration of water quality degradation ecosystem functioning for a long distance downstream. To evaluate these impacts, distributed pollutant transport module was developed on the basis BTOPMC (Block-Wise Use TOPMODEL with Muskingum-Cunge Method), grid-based hydrological model, using flow routing process as carrier due direct runoff. The...

Abstract. Applications of simple lumped parameter models to describe aspects hydrological systems rest on assumptions homogeneity that are rarely valid. The parameters supposed represent the quantities within system as well those overall system, but such will obviously vary greatly from place heterogeneous systems. Less appreciated is fact aggregation errors affect well. Kirchner (2016a) recently demonstrated due heterogeneity in catchments could cause severe underestimation mean transit...

We introduce a global river discharge simulation system based on the BTOP models for individual basins (Global BTOP) and apply Global to quantify flood drought hazards globally.The model utilizes modified topographic index simulates runoff processes including snowmelt, overland flow, soil moisture in root unsaturated zones, sub-surface discharge.The is constructed from available network data 10-arcmin (about 20-km) grid current version.The topographical features are obtained using upscaling...

Following the accident at Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011, large quantities of radioactive materials were released into atmosphere and ocean. Since FDNPP nuclear accident, Tokyo Electric Company (TEPCO) operators have been implementing measures to reduce groundwater inflow damaged reactor buildings while pumping water cool the nuclear reactors fuel debris. The resulting huge volume began discharge ocean from August 2023, after being treated by an Advanced...

Regional finite-difference models tend to have large cell sizes, often on the order of 1-2 km a side. Although regional flow patterns in deeper formations may be adequately represented by such model, intricate surface water and groundwater interactions shallower layers are not. Several stream reaches nearby wells occur single cell, precluding any meaningful modeling between individual features. We propose replace upper MODFLOW layer or layers, which occur, an analytic element model (GFLOW)...

Abstract. This study introduces a flood hazard assessment part of the global risk (Part 2) conducted with distributed hydrological Block-wise TOP (BTOP) model and GIS-based Flood Inundation Depth (FID) model. In this study, 20 km grid BTOP was developed globally available data on applied for Ganges, Brahmaputra Meghna (GBM) river basin. The calibrated observed discharges in Bangladesh climate change impact to produce at each cell under present future climates. For Bangladesh, cumulative...

During the accident in April 1986, Cooling Pond (CP) of Chornobyl Nuclear Power Plant (ChNPP) was heavily contaminated by fuel particles and radionuclides cesium-137 (137Cs) strontium-90 (90Sr). Starting from end 2014, a gradual decrease CP water level began leading to transformation whole reservoir into eight separate sectors raising concern fate 137Cs 90Sr future. In this study, two mathematical models were applied reproduce radioactive contamination 1986 2021 provide forecast...

Environmental tritium (3H) radioisotope with a half-life of 12.32 years is naturally generated in the upper atmosphere by cosmic rays and enters water cycle troposphere as molecule (HTO) to become useful tracer Japan other countries. In 2011, anthropogenic 3H entered terrestrial due Fukushima Daiichi Nuclear Power Plant (FDNPP) atmospheric release discharged Advanced Liquid Processing System (ALPS) treated from FDNPP site Pacific Ocean 2023 raising concerns internationally. Japan,...

Abstract. The African regions have been affected by frequent flood-related disasters. To support decision-makers in flood disaster management, a real-time monitoring system was established the Niger and Volta basins under Water platform to enhance climate resilience Africa (WADiRE-Africa). bridge gap between data unavailability inaccessibility, near-real-time satellite rainfall (GSMaP-NRT) evaluated found very low correlation (<0.4) with gauge at daily scales higher (>0.7) monthly...