Application of Entropy Method to Quantify Future Ecological Flow in the Yellow River Basin

Due to both anthropogenic and climate change impacts, precipitation and runoff in the Yellow River basin have decreased in the past 50 years, leading to more pressure in sustaining human beings and ecosystem needs. It is essential to evaluate the flow condition in the Yellow River basin and see whether it may satisfy its ecological flow in the future. Therefore, this study applied an entropy-based method to calculate the flow duration curves from both observed and simulated data to evaluate the impact of climate change on ecological flow in the Yellow River basin. The simulated FDCs from H08 and DBH models show good agreement with each other and fit observation well. Results show that the decadal FDC at each station is generally predicted to be higher or stay in the higher range under both RCP 2.6 and 8.5 scenarios, suggesting an increase in water amount in the future. It is found that the high flows increase much faster than the low flows, resulting in larger slopes than the references ones, which is due to the larger entropy and M values in the future. At most of the stations, the future values of Q95 and Q90 will safely exceed the threshold. It is found that at the Lanzhou, Wubao, Longmen, and Huayuankou stations, there will be no or little threat to future ecological flow. Still, at the Toudaoguai and Sanmanxia stations, the ecological requirement is not always satisfied. The water stress at the Tangnaihai station from the upper stream of the Yellow River may be threatened in the future.

The California Environmental Flows Framework: Meeting the Challenges of Developing a Large-Scale Environmental Flows Program

Environmental flow programs aim to protect aquatic habitats and species while recognizing competing water demands. Often this is done at the local or watershed level because it is relatively easier to address technical and implementation challenges at these scales. However, a consequence of this approach is that ecological flow criteria are developed for only a few areas as dictated by funding and interest with many streams neglected. Here we discuss the collaborative development of the California Environmental Flows Framework (CEFF) as an example process for developing environmental flow recommendations at a statewide scale. CEFF uses a functional flows approach, which focuses on protecting a broad suite of ecological, geomorphic, and biogeochemical functions instead of specific species or habitats, and can be applied consistently across diverse stream types and spatial scales. CEFF adopts a tiered approach in which statewide models are used to estimate ecological flow needs based on natural functional flow ranges, i.e., metrics that quantify the required magnitude, timing, duration, frequency, and/or rate-of-change of functional flow components under reference hydrologic conditions, for every stream reach in the state. Initial flow needs can then be revised at regional, or watershed, scales based on local constraints, management objectives, and available data and resources. The third tier of CEFF provides a process for considering non-ecological flow needs to produce a final set of environmental flow recommendations that aim to balance of all desired water uses. CEFF was developed via a broad inclusive process that included technical experts across multiple disciplines, representatives from federal and state agencies, and stakeholders and potential end-users from across the state. The resulting framework is therefore not associated with any single agency or regulatory program but can be applied under different contexts, mandates and end-user priorities. The inclusive development of CEFF also allowed us to achieve consensus on the technical foundations and commitment to applying this approach in the future.

Ecological Water Requirement in Upper and Middle Reaches of the Yellow River Based on Flow Components and Hydraulic Index

Deterioration of the ecological environment in the upper and middle reaches of the Yellow River in China substantially impacts the growth and development of aquatic organisms in the drainage basin. This paper builds a conceptual model by applying flow components and fish ecological requirements relation with a relevant object of main fish in the upper and middle reaches of the Yellow River. The paper utilized the flow restoration method by employing the River2D model (two-dimensional model of river hydrodynamics and fish habitat), and a one-dimensional hydrodynamics HEC-RAS (hydrologic engineering center’s-river analysis system). The calculation result showed that the runoff condition required for Silurus lanzhouensis survival is that the monthly lowest flow in a year is 150 m3·s−1, and the lowest flow for suitable flow from April to October is 150 m3·s−1, and 300 m3·s−1 from November to March. The research result is closer to the actual condition and has more outstanding operability. Meanwhile, the results proposed the coupling method of ecological water requirement for the mainstream of the Yellow River. Moreover, the results portrayed the ecological flow process according to the upper envelope of minimum and maximum ecological water requirements of each fracture surface. It is regarded that the ecological flow process is deemed as the initial value of the reservoir regulation model.

Ecosystem Services Linked to Water and Plant Diversity in the Igualata Paramo of Hualcanga Region

The present investigation proposes to study the ecosystem services linked to water and floristic diversity in the Igualata paramo of the Hualcanga region; 5 sampling plots of 25 m2 were installed, with 4 subplots of 1 m2. 30 samples of terrestrial vascular plants were obtained, identifying 17 botanical families, 26 genera, and 27 species, and 1 lichen and 1 moss of unidentified family and genus. It was determined that the species that stands out with the highest importance value index was Lachemilia orgiculata with 44.06%, because the species was found in 4 of the 5 study plots. In second place we have Calamagrostis intermedia species with 8.21%, while the species Vicea sp. was the species with the lowest importance value index of 0.50%, being the species with the lowest number of individuals. The Rosaceae family presented the highest index with 39.61%. The Poaceae and Asteraceae families also present dominance in this ecosystem with values of 9.63% and 5.79%, respectively. According to the Shannon index, plots P2 and P4 were those with high diversity, which corroborates with what was obtained in the Simpson index; the Sorensen index showed us that plots P4 and P5 are very similar, plots P1 and P3 are fairly similar, and the remaining plots are dissimilar, which indicated that vegetation can be found in certain areas of the investigation. The water flow supplying the resident families of the region was found to be 8.12 L/s, and its ecological flow is of 0.83 L/s, having a flow that satisfies the needs of the inhabitants. Keywords: caudal, ecological flow, ecosystem paramo, ecosystem services, floristic diverity, indices of diversity. Resumen La presente investigación propone: estudiar los servicios ecosistémicos ligados al agua y diversidad florística en el páramo del Igualata regional Hualcanga; se instalaron cinco parcelas de muestreo de 25 m2 con 4 sub parcelas de 1 m2, se obtuvo 30 muestras de plantas vasculares terrestres, identificando 17 familias botánicas, 26 géneros y 27 especies, además se colectó 1 liquen y 1 musgo de familia, género y especie no identificado. Se determinó que la especie que sobresale con mayor índice de valor de importancia fue Lachemilia orgiculata con un 44,06%, esto se debe a que la especie se encontraba en 4 de las 5 parcelas de estudio, en segundo lugar, tenemos a Calamagrostis intermedia especie con 8,21%, mientras que la especie Vicea sp. fue la que menor índice de valor de importancia presentó con un 0,50% esto se debe a que fue la especie con menor cantidad de individuos. La familia Rosaceae presentó el mayor índice con 39,61%, las familias Poaceae, y Asteraceae presentan una dominancia en este ecosistema con valores de 9,63% 5,79%, respectivamente. De acuerdo al índice de Shannon las parcelas 2 y 4 son las que poseen diversidad alta que se corrobora con lo obtenido en el índice de Simpson; en el índice de Sorensen nos muestra que las parcelas P4 vs P5 son muy similares las parcelas P1 y P3 son medianamente similares y las parcelas restantes son disimiles lo que indica que la vegetación se puede encontrar en ciertas zonas de la investigación. El caudal que posee la Regional es de 8,12 L/s, abasteciendo a las familias y su caudal ecológico es de 0,83 L/s teniendo un caudal que satisface las necesidades de los pobladores. Palabras clave: caudal, caudal ecológico, diversidad florística, ecosistema páramo, índices de diversidad, servicios ecosistémicos.

Ecological Flow to Protect Aquatic Resources on the Cebadas River, Chambo River Basin

The assessment of ecological flow is a great challenge, which has important implications in the protection of aquatic ecosystems and socio-economic development of an area. The Tennant-Montana method provides the ability to determine ecological flows considering the relationship between aquatic habitat conditions and the average annual flow of a channel. This research presents an estimat∫e of the ecological flow at 10, 30 and 60% of the average flow and trends of the Cebadas River located in the central Andes of Ecuador through a hydrological approach during the period 1966 to 2015. The results allowed to determine an average annual flow rate of 20,768 m3/s and identify a period of avenues (May-September) and a period of dry (October-April). Long-term trend analysis using linear regression and Spearman Rho's test determined that the flow rate has remain Zvirtually unchanged for 50 years and for decade periods. The selected ecological flow was 30% of the seasonal average with values of 6.22 m3/s and 8.32 m3/s for the dry and avenue period respectively. The hydrological variability of the Cebadas River was considered because it is a restrictive factor for the development of the different aquatic species. Flow rates at 30% flow could ensure adequate development and conservation of the aquatic habitats of the Barley River while ensuring a sufficient supply of water for food security. Keywords: Cebadas River, ecological flow, trends, tennant. Resumen La evaluación del caudal ecológico es un gran desafío, que tiene importantes implicaciones en la protección de ecosistemas acuáticos y desarrollo socioeconómico de una zona. El método de Tennant-Montana provee la capacidad de determinar caudales ecológicos considerando la relación entre las condiciones del hábitat acuático y el flujo anual medio de un cauce. Esta investigación presenta una estimación del caudal ecológico al 10, 30 y 60% del caudal medio y tendencias del río Cebadas ubicado en los Andes centrales del Ecuador mediante un enfoque hidrológico durante el periodo de 1966 al 2015. Los resultados permitieron determinar un caudal promedio anual de 20.768 m3/s e identificar un periodo de avenidas (mayo- septiembre) y otro de estiaje (octubre-abril). El análisis de tendencias a largo plazo mediante la regresión lineal y el test de Spearman Rho determinaron que el caudal se ha mantenido prácticamente sin cambios durante 50 años y para los períodos decadales. El caudal ecológico seleccionado fue al 30% de la media estacional con valores de 6.22 m3/s y 8.32 m3/s para el periodo de estiaje y avenida respectivamente. Se consideró la variabilidad hidrológica del río Cebadas porque constituye un factor restrictivo para el desarrollo de las diferentes especies acuáticas. Los caudales al 30% de flujo podrían asegurar un desarrollo y conservación adecuada de los hábitats acuáticos del río Cebada y al mismo tiempo garantiza un suministro suficiente de agua para la seguridad alimentaria. Palabras claves: río Cebadas, régimen fluvial, tendencias, tennant.