scholarly journals Rice paddy irrigation seasonally impacts stream benthic macroinvertebrate diversity at the catchment level

Ecosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Chia‐Ying Ko ◽  
Satoshi Asano ◽  
Meng‐Ju Lin ◽  
Tohru Ikeya ◽  
Elfritzson M. Peralta ◽  
...  
Keyword(s):  
Rice Paddy ◽  
Benthic Macroinvertebrate ◽  
Paddy Irrigation

Benthic macroinvertebrate biodiversity improved with irrigation ponds linked to a rice paddy field

2016 ◽  
Vol 46 (1) ◽  
pp. 70-79 ◽  
Author(s):  
Lak Jung Choe ◽  
Kwang Jin Cho ◽  
Min Su Han ◽  
Min Kyeong Kim ◽  
Soon Kun Choi ◽  
...  
Keyword(s):  
Paddy Field ◽  
Rice Paddy ◽  
Benthic Macroinvertebrate ◽  
Rice Paddy Field

scholarly journals Quantification of seasonal variabilities in groundwater discharge in an extensive irrigation watershed using H, O, and Sr isotopes

2018 ◽  
Author(s):  
Takeo Yoshida ◽  
Takanori Nakano ◽  
Ki-cheol Shin ◽  
Takeo Tsuchihara ◽  
Hiroki Minakawa ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Surface Water ◽  
Groundwater Discharge ◽  
Rice Paddy ◽  
Sr Isotopes ◽  
Watershed Scale ◽  
Isotopic Compositions ◽  
Irrigation Period ◽  
Paddy Irrigation ◽  
Stable Isotopes Of Water

Abstract. Numerous studies have quantified stream–groundwater interactions using geochemical or environmental tracers. However, in watersheds where water is extensively used for rice paddy irrigation, uncertainties in estimation remain due to kinetic fractionation of stable isotopes during evaporation from ponded paddies and seasonal variations of the isotopic composition of recharged water. In this study, we used three different methods (streamflow observation, stable isotopes of water, and Sr isotopes) to quantify groundwater discharge to streams in a watershed substantially impacted by rice paddy irrigation in central Japan. We conducted point- and watershed-scale observations of surface water, soil water, groundwater, and ponded water in rice paddies and examined changes in these isotopic compositions. Point-scale observations revealed that Sr isotopes were more appropriate for quantification because the Sr isotopes in groundwater was significantly different from surface water and less variable in time compared to water isotopes. At watershed-scale, isotopic compositions of stream water changed linearly from upstream end to downstream end, suggesting streamflow consisted of two endmembers. We then quantified groundwater discharge to the stream based on measurement of streamflow and surface lateral inflow/outflow during both irrigation and non-irrigation periods. This water balance method yielded large uncertainties in the estimation due to errors in streamflow measurement, while Sr isotopes provided well constrained estimates during both irrigation and non-irrigation periods. The ratios of groundwater to the stream, estimated from Sr isotopes, was in the range 7–86 % during the irrigation period and 38–66 % during the non-irrigation period. Stable isotopes of water also provided good estimates during the non-irrigation period but underestimated groundwater discharge during the irrigation period due to the ill-defined groundwater end member. The use of Sr isotopes has the potential to aid in quantification of temporal variations in groundwater discharge and to provide important information for water resource managers.

Integration of the rice paddy water management into a coupled surface-subsurface water flow model in the Sakuragawa River watershed (Japan)

2015 ◽  
Vol 47 (1) ◽  
pp. 137-156
Author(s):  
Masaki Sagehashi ◽  
Hiroko Mori ◽  
Yuta Hareyama ◽  
Kazuyuki Sakuma ◽  
Michihiro Akiba ◽  
...  
Keyword(s):  
Water Management ◽  
Water Flow ◽  
Water Resource Management ◽  
Three Dimensional ◽  
Rice Paddy ◽  
Subsurface Water ◽  
Model Parameters ◽  
River Watershed ◽  
Paddy Water ◽  
Paddy Irrigation

Rice paddy water management was integrated into a distributed three-dimensional surface and subsurface coupling hydrological model of the Sakuragawa River watershed. This watershed is located in the Kanto Plain in Japan and includes the hillside of Mt. Tsukuba. Therefore, this watershed includes both steep mountainous areas and rice paddy-dominated flat land. Thus, water management of rice paddies is important and was calculated separately using a paddy model. The use of groundwater for rice paddy irrigation was considered as well as a water supply from outside of the watershed (Kasumigaura Lake). The model parameters were calibrated and validated with reference to the predictability of river water flow and the groundwater level. Using the calibrated model, three-dimensional streamlines, water travel time distributions, and water balance in some grids were clarified. The developed model will facilitate sustainable water resource management in the watershed.

scholarly journals Combined impact of pesticides and other environmental stressors on taxonomic richness of freshwater animals in irrigation ponds

2020 ◽  
Author(s):  
Hiroshi C. Ito ◽  
Hiroaki Shiraishi ◽  
Megumi Nakagawa ◽  
Noriko Takamura
Keyword(s):  
Model Selection ◽  
Environmental Variables ◽  
Rice Paddy ◽  
Habitat Destruction ◽  
Environmental Stressors ◽  
Physical Habitat ◽  
Taxonomic Richness ◽  
Paddy Irrigation ◽  
Wide Range ◽  
Highly Correlated

AbstractRice paddy irrigation ponds can sustain surprisingly high taxonomic richness and make significant contributions to regional biodiversity. We evaluated the impacts of pesticides and other environmental stressors on the taxonomic richness of freshwater animals in 21 irrigation ponds in Japan. We sampled a wide range of freshwater animals (reptiles, amphibians, fishes, mollusks, crustaceans, insects, annelids, bryozoans, and sponges) and surveyed environmental variables related to pesticide contamination, eutrophication, decreased macrophyte coverage, physical habitat destruction, and invasive alien species. Statistical analyses comprised contraction of highly correlated environmental variables, best-subset model selection, stepwise model selection, and permutation tests. Results showed that: (i) probenazole (fungicide) was the unique significant stressor on fish (i.e., contamination with this compound had a significantly negative correlation with fish taxonomic richness), (ii) the interaction of BPMC (insecticide; also known as fenobucarb) and bluegill (invasive alien fish) was a significant stressor on a “large insect” category (Coleoptera, Ephemeroptera, Hemiptera, Lepidoptera, Odonata, and Trichoptera), (iii) the interaction of BPMC and concrete bank was a significant stressor on an “invertebrate” category, (iv) the combined impacts of BPMC and the other stressors on the invertebrate and large insect categories resulted in an estimated mean loss of taxonomic richness by 15% and 77%, respectively, in comparison with a hypothetical pond with preferable conditions.

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