The changes in the annual distribution of mountain runoff during the period of 1965-2018 in Hexi Corridor,Northwest China

The annual distribution characteristics of river runoff in arid regions have significant implications for water resource stability and management.Based on the mountain runoff data from 1965 to 2018,this study examines the annual change characteristics of monthly runoff of the Shiyang River Basin,Heihe River Basin,and Shule River Basin in the Hexi Corridor,Northwest China.Many indexes are used and analyzed,including the coefficient of variance,the complete regulation coefficient,the concentration degree and concentration period,the magnitude of change,the skewness coefficient,and the kurtosis coefficient of the annual distribution curves.The results reveal the following:(1)The inhomogeneity of annual runoff distribution in the Taolai River and the rivers to the west of it,except the Shiyou River,show an increasing trend.Conversely,the inhomogeneity of the rivers to the east of the Taolai River generally show a downward trend,but the coefficient of variance value is still very high.(2)In the Shiyang River Basin,the annual distribution of the concentration period is characterized by a relatively discrete pattern.Conversely,the Heihe River Basin exhibits a relatively concentrated pattern,and the distribution pattern of the Shule River Basin is quite different.Notably,all concentration periods in the three basins have shifted backward after the 2000s.(3)The Shiyang River Basin exhibits disordered annual distribution curves of runoff in different years.In contrast,the Heihe River Basin presents a typical‘single-peak’pattern with a prominent right-skewed.The Shule River Basin has regular distribution curves,with a gradually significant‘double-peak’pattern from east to west.Overall,there has been a slight change in runoff in the Shiyang River Basin,while the Heihe River Basin and Shule River Basin have experienced significant increases in runoff.The annual distribution curves of runoff in the Liyuan River and the rivers to the east of it exhibit a gentle peak pattern,and the appearance probability of extreme runoff during the year is low.Conversely,the rivers to the west of the Liyuan River,excluding the Danghe River,display a sharp peak and thick tail pattern,indicating that the appearance probability of extreme runoff during the year is high.These findings have practical implications for the planning and management of water resources in the Hexi Corridor.Moreover,they provide a solid foundation for predicting future changes in regional water resources.

Assessment of runoff changes in the sub-basin of the upper reaches of the Yangtze River basin, China based on multiple methods

Quantitative assessment of the impact of climate variability and human activities on runoff plays a pivotal role in water resource management and maintaining ecosystem integrity.This study considered six sub-basins in the upper reaches of the Yangtze River basin,China,to reveal the trend of the runoff evolution and clarify the driving factors of the changes during 1956–2020.Linear regression,Mann-Kendall test,and sliding t-test were used to study the trend of the hydrometeorological elements,while cumulative distance level and ordered clustering methods were applied to identify mutation points.The contributions of climate change and human disturbance to runoff changes were quantitatively assessed using three methods,i.e.,the rainfall-runoff relationship method,slope variation method,and variable infiltration capacity(Budyko)hypothesis method.Then,the availability and stability of the three methods were compared.The results showed that the runoff in the upper reaches of the Yangtze River basin exhibited a decreasing trend from 1956 to 2020,with an abrupt change in 1985.For attribution analysis,the runoff series could be divided into two phases,i.e.,1961–1985(baseline period)and 1986–2020(changing period);and it was found that the rainfall-runoff relationship method with precipitation as the representative of climate factors had limited usability compared with the other two methods,while the slope variation and Budyko hypothesis methods had highly consistent results.Different factors showed different effects in the sub-basins of the upper reaches of the Yangtze River basin.Moreover,human disturbance was the main factor that contributed to the runoff changes,accounting for 53.0%–82.0%;and the contribution of climate factors to the runoff change was 17.0%–47.0%,making it the secondary factor,in which precipitation was the most representative climate factor.These results provide insights into how climate and anthropogenic changes synergistically influence the runoff of the upper reaches of the Yangtze River basin.

Straw mulching alters the composition and loss of dissolved organic matter in farmland surface runoff by inhibiting the fragmentation of soil small macroaggregates

Straw mulching is a widespread practice for reducing the soil carbon loss caused by erosion.However,the effects of straw mulching on dissolved organic matter(DOM)runoff loss from black soil are not well studied.How straw mulching affects the composition and loss of runoff DOM by changing soil aggregates remains largely unclear.Here,a straw mulching treatment was compared to a no mulching treatment(as a control)on sloping farmland with black soil erosion in Northeast China.We divided the soil into large macroaggregates(>2 mm),small macroaggregates(0.25-2 mm),and microaggregates(<0.25 mm).After five rain events,the effects of straw mulching on the concentration(characterized by dissolved organic carbon(DoC)and composition(analyzed by fluorescence spectroscopy)of runoff and soil aggregate DOM were studied.The results showed that straw mulching reduced the runoff amount by 54.7%.Therefore,although straw mulching increased the average DOc concentration in runoff,it reduced the total runoff DOM loss by 48.3%.The composition of runoff DOM is similar to that of soil,as both contain humic-like acid and protein-like components.With straw mulching treatment,the protein-like components in small macroaggregates accumulated and the protein-like components in runoff declined with rain events.Fluorescence spectroscopy technology may help in understanding the hydrological paths of rain events by capturing the dynamic changes of runoff and soil DOM characteristics.A variation partitioning analysis(VPA)indicated that the DOM concentration and composition of microaggregates explained 68.2%of the change in runoff DOM from no mulching plots,while the change in runoff DOM from straw mulching plots was dominated by small macroaggregates at a rate of 55.1%.Taken together,our results demonstrated that straw mulching reduces the fragmentation of small macroaggregates and the loss of microaggregates,thus effecting DOM compositions in soil and reducing the DOM loss in runoff.These results provide a theoretical basis for reducing carbon loss in sloping farmland.

Annual variation of adult survival of a south-temperate House Wren population in Argentina

Identifying factors affecting the survival of individuals is essential for understanding the evolution of life-history traits and population dynamics.Despite numerous studies on this subject in north-temperate environments,there is a lack of equivalent studies at similar latitudes in the south.Here,we used a 14-year dataset of capture,banding,and resighting to estimate the annual variation in the apparent adult survival probability of a south-temperate population of House Wrens(Troglodytes aedon bonariae).We evaluated temporal variation in sur-vival and the effect of environmental(climatic)and demographic variables(adult abundance,total number of fledglings produced during each breeding season)on survival estimators.We found that the probability of adult survival decreased as the abundance of breeding adults increased.This density-dependent effect could be related to the resident lifestyle of southern House Wrens,which could determine an intense competition for territories and resources that ultimately would affect their survival.

Responses of runoff to changes in climate and human activities in the Liuhe River Basin, China

Since the 1950s,numerous soil and water conservation measures have been implemented to control severe soil erosion in the Liuhe River Basin(LRB),China.While these measures have protected the upstream soil and water ecological environment,they have led to a sharp reduction in the downstream flow and the deterioration of the river ecological environment.Therefore,it is important to evaluate the impact of soil and water conservation measures on hydrological processes to assess long-term runoff changes.Using the Soil and Water Assessment Tool(SWAT)models and sensitivity analyses based on the Budyko hypothesis,this study quantitatively evaluated the effects of climate change,direct water withdrawal,and soil and water conservation measures on runoff in the LRB during different periods,including different responses to runoff discharge,hydrological regime,and flood processes.The runoff series were divided into a baseline period(1956-1969)and two altered periods,i.e.,period 1(1970-1999)and period 2(2000-2020).Human activities were the main cause of the decrease in runoff during the altered periods,contributing 86.03%(-29.61 mm),while the contribution of climate change was only 13.70%(-4.70 mm).The impact of climate change manifests as a decrease in flood volume caused by a reduction in precipitation during the flood season.Analysis of two flood cases indicated a 66.00%-84.00%reduction in basin runoff capacity due to soil and water conservation measures in the upstream area.Soil and water conservation measures reduced the peak flow and total flood volume in the upstream runoff area by 77.98%and 55.16%,respectively,even with nearly double the precipitation.The runoff coefficient in the reservoir area without soil and water conservation measures was 4.0 times that in the conservation area.These results contribute to the re-evaluation of soil and water conservation hydrological effects and provide important guidance for water resource planning and water conservation policy formulation in the LRB.

Runoff change in the Yellow River Basin of China from 1960 to 2020 and its driving factors

Analysing runoff changes and how these are affected by climate change and human activities is deemed crucial to elucidate the ecological and hydrological response mechanisms of rivers.The Indicators of Hydrologic Alteration and the Range of Variability Approach(IHA-RVA)method,as well as the ecological indicator method,were employed to quantitatively assess the degree of hydrologic change and ecological response processes in the Yellow River Basin from 1960 to 2020.Using Budyko's water heat coupling balance theory,the relative contributions of various driving factors(such as precipitation,potential evapotranspiration,and underlying surface)to runoff changes in the Yellow River Basin were quantitatively evaluated.The results show that the annual average runoff and precipitation in the Yellow River Basin had a downwards trend,whereas the potential evapotranspiration exhibited an upwards trend from 1960 to 2020.In approximately 1985,it was reported that the hydrological regime of the main stream underwent an abrupt change.The degree of hydrological change was observed to gradually increase from upstream to downstream,with a range of 34.00%-54.00%,all of which are moderate changes.However,significant differences have been noted among different ecological indicators,with a fluctuation index of 90.00%at the outlet of downstream hydrological stations,reaching a high level of change.After the mutation,the biodiversity index of flow in the middle and lower reaches of the Yellow River was generally lower than that in the base period.The research results also indicate that the driving factor for runoff changes in the upper reach of the Yellow River Basin is mainly precipitation,with a contribution rate of 39.31%-54.70%.Moreover,the driving factor for runoff changes in the middle and lower reaches is mainly human activities,having a contribution rate of 63.70%-84.37%.These results can serve as a basis to strengthen the protection and restoration efforts in the Yellow River Basin and further promote the rational development and use of water resources in the Yellow River.

Glacier area change and its impact on runoff in the Manas River Basin,Northwest China from 2000 to 2020

Understanding the distribution and dynamics of glaciers is of great significance to the management and allocation of regional water resources and socio-economic development in arid regions of Northwest China.In this study,based on 36 Landsat images,we extracted the glacier boundaries in the Manas River Basin,Northwest China from 2000 to 2020 using eCognition combined with band operation,GIS(geographic information system)spatial overlay techniques,and manual visual interpretation.We further analyzed the distribution and variation characteristics of glacier area,and simulated glacial runoff using a distributed degree-day model to explore the regulation of runoff recharge.The results showed that glacier area in the Manas River Basin as a whole showed a downward trend over the past 21 a,with a decrease of 10.86%and an average change rate of–0.54%/a.With the increase in glacier scale,the number of smaller glaciers decreased exponentially,and the number and area of larger glaciers were relatively stable.Glacier area showed a normal distribution trend of increasing first and then decreasing with elevation.About 97.92%of glaciers were distributed at 3700–4800 m,and 48.11%of glaciers were observed on the northern and northeastern slopes.The retreat rate of glaciers was the fastest(68.82%)at elevations below 3800 m.There was a clear rise in elevation at the end of glaciers.Glaciers at different slope directions showed a rapid melting trend from the western slope to the southern slope then to the northern slope.Glacial runoff in the basin showed a fluctuating upward trend in the past 21 a,with an increase rate of 0.03×10^(8) m^(3)/a.The average annual glacial runoff was 4.80×10^(8) m^(3),of which 33.31%was distributed in the ablation season(June–September).The average annual contribution rate of glacial meltwater to river runoff was 35.40%,and glacial runoff accounted for 45.37%of the total runoff during the ablation season.In addition,precipitation and glacial runoff had complementary regulation patterns for river runoff.The findings can provide a scientific basis for water resource management in the Manas River Basin and other similar arid inland river basins.

Comparative Assessment of Impacts of Future Climate Change on Runoff in Upper Daqinghe Basin,China

Assessing runoff changes is of great importance especially its responses to the projected future climate change on local scale basins because such analyses are generally done on global and regional scales which may lead to generalized conclusions rather than specific ones.Climate change affected the runoff variation in the past in the upper Daqinghe Basin,however,the climate was mainly considered uncertain and still needs further studies,especially its future impacts on runoff for better water resources management and planning.Integrated with a set of climate simulations,a daily conceptual hydrological model(MIKE11-NAM)was applied to assess the impact of climate change on runoff conditions in the Daomaguan,Fuping and Zijingguan basins in the upper Daqinghe Basin.Historical hydrological data(2008–2017)were used to evaluate the applicability of the MIKE11-NAM model.After bias correction,future projected climate change and its impacts on runoff(2025–2054)were analysed and compared to the baseline period(1985–2014)under three shared social economic pathways(SSP1-2.6,SSP2-4.5,and SSP5-8.5)scenarios from Coupled Model Intercomparison Project Phase 6(CMIP6)simulations.The MIKE-11 NAM model was applicable in all three Basins,with both R^(2)and Nash-Sutcliffe Efficiency coefficients greater than 0.6 at daily scale for both calibration(2009–2011)and validation(2012–2017)periods,respectively.Although uncertainties remain,temperature and precipitation are projected to increase compared to the baseline where higher increases in precipitation and temperature are projected to occur under SSP2-4.5 and SSP5-8.5 scenarios,respectively in all the basins.Precipitation changes will range between 12%–19%whereas temperature change will be 2.0℃–2.5℃ under the SSP2-4.5 and SSP5-8.5 scenarios,respectively.In addition,higher warming is projected to occur in colder months than in warmer months.Overall,the runoff of these three basins is projected to respond to projected climate changes differently because runoff is projected to only increase in the Fuping basin under SSP2-4.5 whereas decreases in both Daomaguan and Zijingguan Basins under all scenarios.This study’s findings could be important when setting mitigation strategies for climate change and water resources management.

Runoff Characteristics of Different Stands in Dongjiang Lake Reservoir Area

Different forest stands in the Dongjiang Lake Reservoir area of Zixing were selected as the research objects to study the characteristics of runoff generation in different forest stands.The results showed that there was no significant difference in annual runoff among M3,M1,and M5,and no significant difference between each forest stand and the control.The order was M3(22.75 mm)>M1(21.77 mm)>M5(20.14 mm).Forest vegetation generates less runoff through vegetation restoration compared to the control,indicating that forest vegetation reconstruction and restoration are beneficial for soil and water conservation.

Fragipan Horizon Changes Using Annual Ryegrass and Other Admendments

A greenhouse experiment was conducted involving intact fragipan soil cores of 50 cm thickness after removing the topsoil horizons. The cores were maintained in moist condition throughout the experiment and received several treatments with various amendments for different periods ranging from 9 to 17 months. The amendments included annual ryegrass or Festulolium residues, powder limestone and various humate compounds alone or in combination with the grass residues. The results suggested a significant effect of ryegrass and Festulolium in reducing penetration resistance into the top 10 cm of the fragipan within 9 - 17 months, particularly when used in combination with certain humate materials such as Leonardite. Apparently, this is the result of the release of certain soluble organic compounds from the plant residues or the humate amendments that increase the solubility of Si and Al associated with the fragipan brittleness, thus decreasing the density of the compacted fragipan material.

Analysis on the Variations of Annual Runoff Distribution in the Weihe Basin

With the impact of climate change and the increasing intensity of human activities,the hydrological regime had changed,including annual runoff distribution,which was related with water resources management and ecological construction. Based on the monthly runoff data for more than 40 years of the Beidao,Xianyang,Huaxian station on Weihe Basin,the annual distribution characteristics of runoff were studied. Several indices related to attributes of uneven,concentrate degree and variation amplitude were calculated,and the results showed that there had obvious fresh and drought seasonal changes in 1990s. The annual runoff distribution had changed a lot,mainly because of runoff decrease in the wet season. The Huaxian station,which locates at the upper reaches,had a higher unevenness,concentration and relative variation rate than that of the Beidao and Xianyang station.

Long-term Trend and Fractal of Annual Runoff Process in Mainstream of Tarim River

Based on the time series data from the Aral hydrological station for the period of 1958-2005,the paper re-veals the long-term trend and fractal of the annual runoff process in the mainstream of the Tarim River by using the wavelet analysis method and the fractal theory.The main conclusions are as follows:1)From a large time scale point of view,i.e.the time scale of 16(24)years,the annual runoff basically shows a slightly decreasing trend as a whole from 1958 to 2005.If the time scale is reduced to 8(23)or 4(22)years,the annual runoff still displays the basic trend as the large time scale,but it has fluctuated more obviously during the period.2)The correlation dimension for the annual runoff process is 3.4307,non-integral,which indicates that the process has both fractal and chaotic characteris-tics.The correlation dimension is above 3,which means that at least four independent variables are needed to describe the dynamics of the annual runoff process.3)The Hurst exponent for the first period(1958-1973)is 0.5036,which equals 0.5 approximately and indicates that the annual runoff process is in chaos.The Hurst exponents for the second(1974-1989)and third(1990-2005)periods are both greater than 0.50,which indicate that the annual runoff process showed a long-enduring characteristic in the two periods.The Hurst exponent for the period from 1990 to 2005 indi-cates that the annual runoff will show a slightly increasing trend in the 16 years after 2005.

Documented changes in annual runoff and attribution since the 1950s within selected rivers in China

To enable local water resource management and maintenance of ecosystem integrity and to protect and mitigate against flood and drought, it is necessary to determine changes in long-term series of streamflow and to distinguish the roles that climate change and human disturbance play in these changes. A review of previous research on the detection and attribution of observed changes in annual runoff in China shows a decrease in annual runoff since the 1950s in northern China in areas such as the Songhuajiang River water resources zone, the Liaohe River water resources zone, the Haihe River water resources zone, the Yellow River water resources zone, and the Huaihe River water resources Zone. Furthermore, abrupt changes in annual runoff occurred mostly in the 1970s and 1980s in all the above zones, except for some of the sub-basins in the middle Yellow River where abrupt change occurred in the 1990s. Changes in annual runoff are found to be mainly caused by climate change in the western Songhuajiang River basin, the upper mainstream of the Yangtze River, and the western Pearl River basin, which shows that studies on the impact of climate change on future water resources under different climate change scenarios are required to enable planning and management by agencies in these river basins. However, changes in annual runoff were found to be mainly caused by human activities in most of the catchments in northern China (such as the southern Songhuajiang River, Liaohe River, Haihe River, the lower reach and some of the catchments within the middle Yellow River basin) and in middle-eastern China, such as the Huaihe River and lower mainstream of the Yangtze River. This suggests that current hydro-climatic data can continue to be used in water-use planning and that policymakers need to focus on water resource management and protection.

The complex nonlinear systems with fractal as well as chaotic dynamics of annual runoff processes in the three headwaters of the Tarim River

This paper attempted to identify fractal and chaotic characteristics of the annual runoff processes in headwaters of the Tarim River.Methods of fractal analyses were used to explore several aspects of the temporal changes from 1957 to 2002.The main findings are as follows:(1) The annual runoff processes of the three headwaters of the Tarim River are com-plex nonlinear systems with fractal as well as chaotic dynamics.(2) The correlation dimensions of attractor derived from the time series of the annual runoff for the Hotan,Yarkand and Aksu rivers are all greater than 3.0 and non-integral,implying that all three rivers are chaotic dynamical systems that are sensitive to initial conditions,and the dynamic modeling of their annual runoff process requires at least four independent variables.(3) The time series of annual runoff in each river presents a long-term correlation characteristic.The Hurst exponent for the period of 1989 to 2002 suggests that we may expect to see an increasing trend in the annual runoff of the Aksu and Yarkand rivers in the years after 2002,but a decreasing tendency for the Hotan River in the same period.

Development of a Regional Regression Model for Estimating Annual Runoff in the Hailar River Basin of China

The Hailar River, a first-grade tributary of the Erguna River that borders China and Russia, is the main water source for the local industry and agriculture. However, because there are only 11 flow gauging stations and those stations cannot monitor all runoff paths, it is hard to directly use the existing flow data to estimate the annual runoffs from all subbasins of interest although such estimation is needed for utilization and protection of the water resources in the Hailar River. Thus, this study implemented an indirect approach (i.e., regional regression model) by correlating annual runoff with annual rainfall and water surface evaporation as well as hydrologic characteristics of the 11 subbasins monitored by the gauging stations. The study used 51 years (from 1956 to 2006) data. The results indicated a significant correlation (R2 > 0.87) between annual runoff and the selected subbasin characteristics and showed the model to be robust because the predicted runoffs for the validation period are compatible with the corresponding observed values. In addition, this model was used to estimate the annual runoffs for the subbasins that are not monitored by the 11 flow gauging stations, which adds new information to existing literature.

Quantitative research of annual runoff distribution characteristics in the Dagujia River basin,Yantai,China

Mann-Kendall method and minimum variance method are used in this study to analyze the mean value variable-point of the runoff data observed by Fushan Hydrological Station in the Dagujia River basin from 1966 to 2004. Based on the results, the runoff time is divided into four periods with the similar hydrological variation character. The annual runoff distribution characters in the Dagujia River basin are discussed by using the non-uniform coefficients, concentration degree and concentration period, variation range, etc. The results indicate that: (1) River runoff is very unevenly distributed throughout the year in Dagujia River. About 90% of runoff is in the period from June to October, while the runoff from November to April of the next year is lower. (2) The annual runoff distribution characters during 1966-1971 are very similar to that of 1982-1996, and the runoff of 1972-1981 is almost similar to that of 1997-2004. (3) The annual runoff distribution characters have changed obviously during 1997-2004 compared with the other periods, which makes it more difficult to exploit and use the water resource in the future.

Response of runoff to climate change in the area of runoff yield in upstream Shiyang River Basin,Northwest China:A case study of the Xiying River

The objective of this study was to analyze the response of runoff in the area of runoff yield of the upstream Shiyang River basin to climate change and to promote sustainable development of regional water resources and ecological environment.As the biggest tributary of the Shiyang River,Xiying River is the only hydrological station(Jiutiaoling) that has provincial natural river and can achieve long time series monitoring data in the basin.The data obtained from this station is representative of natural conditions because it has little human activites.This study built a regression model through identifying the characteristics of runoff and climate change by using Mann-Kendall nonparametric statistical test,cumulative anomaly,and correlation analysis.The results show that the average annual runoff is 320.6 million m3/a with the coefficient of variation of 0.18 and shows slightly decrease during 1956-2020.It has a significant positive correlation the average annual precipitation(P<0.01).Runoff is sensitive to climate change,and the climate has becoming warm and wet and annual runoff has entering wet period from 2003.Compared to the earlier period(1955-2000),the increases of average annual temperature,precipitation and runoff in recent two decades were 15%,9.3%,and 7.8%,respectively.Runoff in the Shiyang River is affected by temperature and precipitation among climate factors,and the simulation results of the runoff-climate response model(R=0.0052P-0.1589T+2.373) indicate that higher temperature leads to a weakening of the ecological regulation of surface runoff in the flow-producing area.

Responses of intra-annual runoff to forest recovery patterns in subtropical China

Forest recovery plays a critical role in regulating eco-hydrological processes in forested watersheds.However,characteristics of the intra-annual runoff variation associated with different forest recovery patterns remain poorly understood.In this study,three forest change periods were identified,the baseline period(1961-1985),reforestation period(1986-2000)and fruit tree planting period(2001-2016).We selected the magnitude of seasonal runoff(wet and dry seasons)and distribution characteristics,i.e.,non-uniformity coefficient(C_(v)),complete accommodation coefficient(C_(r)),concentration ratio(C_(n)),concentration period(C_(d)),absolute variation ratio(ΔR)and relative variation ratio(C_(max)).The pair-wise approach evaluated the intra-annual runoff variation characteristics between forest change periods.Results indicate that reforestation decreased wet season runoff and increased dry season runoff.In contrast,fruit tree planting increased wet season runoff and had no significant effect on dry season runoff.For intra-annual runoff distribution characteristics,reforestation significantly reduced the C_(v),C_(r),C_(n)and C_(max).Distribution of the intra-annual runoff in the fruit tree planting period was not significantly different from the baseline.We concluded that reforestation reduced the occurance of extreme water conditions in wet and dry seasons and effectively increased the stability of the intra-annual runoff.In contrast,fruit tree planting increased instability and fluctuation of the intra-annual runoff after reforestation.The characteristics of the intra-annual runoff to fruit tree planting was similar to those of the baseline.Therefore,adopting fruit tree planting practices to regulate intra-annual runoff characteristics may not be a practical approach,and impacts of different reforestation practices should be ascertained in our study region.The implications of this study should guide regional land-water management,and this study adds to the understanding of the impacts gained in forest cover on hydrology.

Annual Runoff and Sediment in Duhok Reservoir Watershed Using SWAT and WEPP Models

Estimation of runoff volume and sediment load is the main problem that affects the performance of dams due to the reduction in the storage capacity of their reservoirs and their effect on dam efficiency and operation schedule. The simulation models can be considered for this purpose if the continuous field measurements are not available. Soil and Water Assessment Tool (SWAT) and Water Erosion Prediction Project (WEPP) models were applied to estimate the annual runoff volume and sediment load for Duhok Dam Reservoir in north of Duhok/Iraq for the period 1988-2011. The estimated annual runoff volume varied from 2.3 to 34.7 MCM for considered period. Those values were affected by rainfall depth, intensity and runoff coefficient. The resultant annual runoff coefficient for the studied area ranged from 0.05 to 0.35 (average was 0.18) causing an average runoff volume of about 14 MCM. The results of sediment routing indicated that the values of sediment yields varied from 50 to 1400 t/km2/year depending on sub basin properties. The average annual sediment load from the whole watershed is about 120 × 103 ton. The estimated total sediment arrived to Duhok Reservoir for the considered period 1988-2011 was about 2.9 × 106 ton. The results indicate that both models gave reasonable results in comparison with measured values. Based on statistical criteria, the results of both models are close to gather.

Histology, physiology, and transcriptomic and metabolomic profiling reveal the developmental dynamics of annual shoots in tree peonies (Paeonia suffruticosa Andr.)

The development of tree peony annual shoots is characterized by“withering”,which is related to whether there are bud points in the leaf axillaries of annual shoots.However,the mechanism of“withering”in tree peony is still unclear.In this study,Paeonia ostii‘Fengdan’and P.suffruticosa‘Luoyanghong’were used to investigate dynamic changes of annual shoots through anatomy,physiology,transcriptome,and metabolome.The results demonstrated that the developmental dynamics of annual shoots of the two cultivars were comparable.The withering degree of P.suffruticosa‘Luoyanghong’was higher than that of P.ostii‘Fengdan’,and their upper internodes of annual flowering shoots had a lower degree of lignin deposition,cellulose,C/N ratio,showing no obvious sclerenchyma,than the bottom ones and the whole internodes of vegetative shoot,which resulted in the“withering”of upper internodes.A total of 36 phytohormone metabolites were detected,of which 33 and 31 were detected in P.ostii‘Fengdan’and P.suffruticosa‘Luoyanghong’,respectively.In addition,302 and 240 differentially expressed genes related to lignin biosynthesis,carbon and nitrogen metabolism,plant hormone signal transduction,and zeatin biosynthesis were screened from the two cultivars.Furtherly,36 structural genes and 40 transcription factors associated with the development of annual shoots were highly co-expressed,and eight hub genes involved in this developmental process were identified.Consequently,this study explained the developmental dynamic on the varied annual shoots through multi-omics,providing a theoretical foundation for germplasm innovation and the mechanized harvesting of tree peony annual shoots.