scholarly journals An Environmental Flow Framework for Riverine Macroinvertebrates During Dry and Wet Seasons Through Non-linear Ecological Modeling

2021 ◽  
Vol 9 ◽  
Author(s):  
Qingyi Luo ◽  
Ming-Chih Chiu ◽  
Lu Tan ◽  
Qinghua Cai

A suitable environmental flow is critical for the functional maintenance of riverine ecosystems. Hydropower plants alter the flow regime by decreasing or even drying up the streamflow downstream of the dams, thereby affecting ecosystem sustainability. In this study, we aimed to develop a robust environmental flow framework that can provide scientific evidence for sustainable water resource management. Using ecological niche modeling based on non-linear responses of species to habitat factors, we assessed the environmental flow in the Xiangxi River Basin of Central China during dry and wet seasons from a multi-year perspective. The most abundant macroinvertebrate taxon (i.e., Baetis) was selected for model testing. The results showed seasonal differences in the minimum ecological water requirements and optimal environmental flow. These two hydrological metrics were higher during the wet season than during the dry season. During the dry season, the minimum ecological water requirement of Baetis was 1.3 m3·s−1, and the optimal environmental flow was 1.6 m3·s−1. During the wet season, the minimum ecological water requirement of Baetis was 2.5 m3·s−1, and the optimal environmental flow was 2.6 m3·s−1. This study provides a theoretical basis for the robust management of water resources in river basins.

2018 ◽  
Vol 1 (4) ◽  
pp. 971-984
Author(s):  
Setia Budi ◽  
Azmeri Azmeri ◽  
Syamsidik Syamsidik

Abstract : Water demand fulfillment in coastal area of Peukan Bada Sub District is still complicated. Peukan Bada Community in coastal area currently still depends on well water. The existence of Lambadeuk Small Dam located in Peukan Bada Sub District – Aceh Besar, which River Flow Area (DAS) is ± 2.27 Km², is expected to be able in fulfilling clean water demand. The objectives of this research are to find out water supply, to optimize the operation and to obtain the reliability of Lambadeuk Small Dam Operation. The method used in operating the small dam is analyzed by Non Linear Program using Solver Microsoft Excel. In optimizing the operation, it is divided into three season conditions. The highest inflow discharge of dry season is in January which is 0.222 m3/sec or 0.594 MCM, while the highest inflow discharge of normal season is in December which is 0.294 m3/sec or 0.787 MCM, and the highest inflow discharge of wet season is in November which is 0. 463 m3/sec or 1.199 MCM. The projection of population and clean water demand for population need in coastal area of Peukan Bada Sub District can be described as for population 5,954 in 2015, the clean water demand is 0.0099 m3/sec so that in 2035, the population will become 10,534 and the clean water demand will be 0.0176 m3/sec. The average inflow from 2015 to 2035 for dry season is 4.031 MCM, for normal season is 5.816 MCM, and for wet season is 9.077 MCM. Water release is 0.312 MCM, and basic water demand is 0.556 MCM. Optimization reliability of Lambadeuk Small Dam Operation is reliable and 100% can fulfill the water demand in the downstream of the small dam, and the management organizer of Lambadeuk Small Dam can also expand service area of clean water demand in the coastal area of Peukan Bada Sub District – Aceh Besar. Abstrak: Dalam pemenuhan kebutuhan air bersih di daerah pesisir Kecamatan Peukan Bada masih kesulitan untuk kebutuhan air bersih. Selama ini masyarakat di daerah pesisir masih mengandalkan air sumur. Dengan adanya Embung Lambadeuk yang terletak di Kecamatan Peukan Bada Kabupaten Aceh Besar, yang mempunyai luas Daerah Aliran Sungai (DAS) ± 2,27 Km², mampu untuk pemenuhan kebutuhan air bersih. Tujuan dari penelitian ini untuk mengetahui ketersediaan air, mengoptimalkan pengopersian dan mendapatkan keandalan pengopersian Embung Lambadeuk. Pada penelitian ini metode pengoperasian embung yang dianalisis menggunakan program Non Linear dengan solver Microsoft Excel. Dalam optimasi pengoperasian dikelompokan dalam tiga kondisi tahun musim, dimana kondisi tahun musim kering debit Inflow yang tertinggi berada pada bulan Januari sebesar 0,222 m3/dt dengan kapasitas  0,594 MCM, pada kondisi tahun normal debit yang tertinggi berada pada bulan  Desember sebesar 0,294 m3/dt  dengan kapasitas  0,787 MCM dan pada kondisi tahun basah debit yang tertinggi pada bulan Nopember sebesar 0,463 m3/dt dengan kapasitas  1,199 MCM. Proyeksi jumlah penduduk dan kebutuhan air bersih untuk pemenuhan penduduk di pesisir Kecmatan Peukan Bada, tahun 2015 dengan jumlah penduduk sebesar 5.954 jiwa, kebutuhan air bersih 0,0099 m3/dt dan Tahun 2035 jumlah penduduk sebesar 10.534 jiwa, kebutuhan air bersih 0,0176 m3/dt. Untuk Inflow tahun kering dari Tahun 2015 sampai Tahun 2035 Inflow rata-rata tahunan sebesar 4,031 MCM, tahun normal dari Tahun 2015 sampai tahun 2035 Inflow rata-rata sebesar 5,816 MCM, dan tahun basah Inflow rata-rata tahunan sebesar 9,077 MCM. Release air sebesar 0.312 MCM, dan kebutuhan air baku sebesar 0,556 MCM. Hasil yang dicapai adalah Pengoperasian Embung yang Optimal dan Keandalan Pengoperasian Embung. Dimana Keandalan Pengoperasian Embung Lambadeuk sangat berpengaruh dari volume dan periode waktu, dan terhadap Manajemen pengelola Embung Lambadeuk, bisa mengambil langkah-langkah untuk memperluas daerah layanan kebutuhan air bersih di pesisir Kecamatan Peukan Bada Aceh Besar.


2021 ◽  
Vol 933 (1) ◽  
pp. 012015
Author(s):  
Adam Rus Nugroho

Abstract The declining groundwater in Yogyakarta could potentially affect the Code River baseflow, thus lowering the river streamflow. Consequently, the riverine ecosystem would suffer from a low quantity of streamflow. The quantity standard of streamflow can be determined by calculating the environmental flow. In this study, the environmental flow requirement (EFR) for the Code River is determined by applying an enhanced version of the most-used hydrological method, namely the Modified Tennant Method based on Multilevel Habitat Conditions III (MTMMHC-III). The EFR in the Code River could be calculated successfully by the MTMMHC-III with a satisfactory temporal variability. The EFRs are the lowest during July to October in the normal years, July to September in the wet years, and July to December in the dry years. The EFRs are highest during January to April in the normal and dry years and January to May in the wet years. However, the EFR might become too low in the dry years, especially from the beginning of the dry season (May) until the early wet season (December), with only 4-11% of the average annual flow. Ultimately, the MTMMHC-III method is a better hydrological method than the original Tennant Method and Q95 method.


2019 ◽  
Vol 11 (23) ◽  
pp. 2872 ◽  
Author(s):  
Syed A. Ali ◽  
Venkataramana Sridhar

The Mekong River basin supported a large population and ecosystem with abundant water and nutrient supply. However, the impoundments in the river can substantially alter the flow downstream and its timing. Using limited observations, this study demonstrated an approach to derive dam characteristics, including storage and flow rate, from remote-sensing-based data. Global Reservoir and Lake Monitor (GRLM), River-Lake Hydrology (RLH), and ICESat-GLAS, which generated altimetry from Jason series and inundation areas from Landsat 8, were used to estimate the reservoir surface area and change in storage over time. The inflow simulated by the variable infiltration capacity (VIC) model from 2008 to 2016 and the reservoir storage change were used in the mass balance equation to calculate outflows for three dams in the basin. Estimated reservoir total storage closely resembled the observed data, with a Nash-Sutcliffe efficiency and coefficient of determination more than 0.90 and 0.95, respectively. An average decrease of 55% in outflows was estimated during the wet season and an increase of up to 94% in the dry season for the Lam Pao. The estimated decrease in outflows during the wet season was 70% and 60% for Sirindhorn and Ubol Ratana, respectively, along with a 36% increase in the dry season for Sirindhorn. Basin-wide demand for evapotranspiration, about 935 mm, implicitly matched with the annual water diversion from 1000 to 2300 million m3. From the storage–discharge rating curves, minimum storage was also evident in the monsoon season (June–July), and it reached the highest in November. This study demonstrated the utility of remote sensing products to assess the impacts of dams on flows in the Mekong River basin.


2019 ◽  
Vol 01 (01) ◽  
pp. 1950001
Author(s):  
ARYA SOMAN ◽  
N. R. CHITHRA

Impact assessment of regional climate change is very important as change in climate has emerged as one of the major threats to water resource systems and would significantly affect streamflow, soil moisture and water availability. The study used output of the Regional Climate Model (RCM) Remo2009 (Max-Planck-Institute (MPI)) to analyze the potential impacts of climate change on irrigated agriculture in the Chaliyar river basin, India. Streamflow and evapotranspiration were simulated using validated Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) model. The estimation of irrigation water requirement (IWR) was performed using Food and Agriculture Organization (FAO) method for the period 2021–2030 and 2051–2060. Results show that projected streamflow increases during June to September and decreases during October to December and January to May in future. Crop water requirement and IWR showed an increase during dry season and decrease during wet season. The increase/decrease in streamflow and IWR during wet/dry season is more in the far future than near future and for RCP 8.5 scenario than RCP 4.5 scenario.


2021 ◽  
pp. 1-57

Abstract Central Asia (CA: 35°-55°N, 55°-90°E) has been experiencing a significant warming trend during the past five decades, which has been accompanied by intensified local hydrological changes. Accurate identification of variations in hydroclimatic conditions and understanding the driving mechanisms are of great importance for water resource management. Here, we attempted to quantify dry/wet variations by using precipitation minus evapotranspiration (P–E) and attributed the variations based on the atmosphere and surface water balances. Our results indicated that the dry season became drier while the wet season became wetter in CA for 1982–2019. The land surface water budget revealed precipitation (96.84%) and vapor pressure deficit (2.26%) as the primary contributing factors for the wet season. For the dry season, precipitation (95.43%), net radiation (3.51%), and vapor pressure deficit (−2.64%) were dominant factors. From the perspective of the atmospheric water budget, net inflow moisture flux was enhanced by a rate of 72.85 kg m−1 s−1 in the wet season, which was mainly transported from midwestern Eurasia. The increase in precipitation induced by the external cycle was 11.93 mm/6month. In contrast, the drying trend during the dry season was measured by a decrease in the net inflow moisture flux (74.41 kg m−1 s−1) and reduced external moisture from midwestern Eurasia. An increase in precipitation during the dry season can be attributed to an enhancement in local evapotranspiration, accompanied by a 4.69% increase in the recycling ratio. The compounding enhancements between wet and dry seasons ultimately contribute to an increasing frequency of both droughts and floods.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xue Zhu ◽  
Jiyue Qin ◽  
Chongyang Tan ◽  
Kang Ning

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.


Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 319
Author(s):  
Cristian Pérez-Granados ◽  
Karl-L. Schuchmann

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.


Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 320
Author(s):  
Qianyao Si ◽  
Mary G. Lusk ◽  
Patrick W. Inglett

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.


2012 ◽  
Vol 63 (9) ◽  
pp. 788 ◽  
Author(s):  
N. E. Pettit ◽  
T. D. Jardine ◽  
S. K. Hamilton ◽  
V. Sinnamon ◽  
D. Valdez ◽  
...  

The present study indicates the critical role of hydrologic connectivity in floodplain waterholes in the wet–dry tropics of northern Australia. These waterbodies provide dry-season refugia for plants and animals, are a hotspot of productivity, and are a critical part in the subsistence economy of many remote Aboriginal communities. We examined seasonal changes in water quality and aquatic plant cover of floodplain waterholes, and related changes to variation of waterhole depth and visitation by livestock. The waterholes showed declining water quality through the dry season, which was exacerbated by more frequent cattle usage as conditions became progressively drier, which also increased turbidity and nutrient concentrations. Aquatic macrophyte biomass was highest in the early dry season, and declined as the dry season progressed. Remaining macrophytes were flushed out by the first wet-season flows, although they quickly re-establish later during the wet season. Waterholes of greater depth were more resistant to the effects of cattle disturbance, and seasonal flushing of the waterholes with wet-season flooding homogenised the water quality and increased plant cover of previously disparate waterholes. Therefore, maintaining high levels of connectivity between the river and its floodplain is vital for the persistence of these waterholes.


1992 ◽  
Vol 43 (2) ◽  
pp. 241 ◽  
Author(s):  
JJ Mott ◽  
MM Ludlow ◽  
JH Richards ◽  
AD Parsons

The close correlation between grazing-induced mortality and major climatic patterns in Australian savannas, led us to the hypothesis that moisture conditions during the dry, non-growing season could affect sensitivity to grazing in the subsequent growing season. Using three widespread savanna species (Themeda triandra, Heteropogon contortus and Panicum maximum), this hypothesis was tested experimentally and the mechanisms controlling this response examined and quantified. In T. triandra drought during the dry season led to major mortality in defoliated plants in the next growing season. This mortality was caused by a synchrony of tillering at the commencement of the wet season, leaving few buds for replacement once parent tillers were killed by defoliation. T. triandra was also the most sensitive species to defoliation. This sensitivity was due to the poor ability of the plant to maintain positive carbon gain after defoliation. Several factors contributed to this poor ability, including: low total photosynthetic rate, low specific leaf area, and a large proportion of sheath material with poor photosynthetic capacity remaining after cutting. Both H. contortus and P. maximum growing under irrigated and fertilized conditions did not display any effects of previous moisture treatments when defoliated during the next wet season and were much less sensitive to defoliation than T. triandra.


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