scholarly journals Simulating a Watershed-Scale Strategy to Mitigate Drought, Flooding, and Sediment Transport in Drylands

Systems ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 53 ◽  
Author(s):  
Connie M. Maxwell ◽  
Saeed P. Langarudi ◽  
Alexander G. Fernald
Keyword(s):  
Sediment Transport ◽  
Water Storage ◽  
The United States ◽  
Process Models ◽  
Management Policy ◽  
Soil Water Storage ◽  
Management Scenarios ◽  
Water Storage Capacity ◽  
Flood Flow

Drylands today are facing a landscape-scale water storage problem. Throughout the increasingly arid Southwest of the United States, vegetation loss in upland watersheds is leading to floods that scour soils and transport sediment that clogs downstream riparian areas and agricultural infrastructure. The resulting higher flow energies and diminished capacity to infiltrate flood flows are depleting soil water storage across the landscape, negatively impacting agriculture and ecosystems. Land and water managers face challenges to reverse the trends due to the complex interacting social and biogeophysical root causes. Presented here is an integrative system dynamics model that simulates innovative and transformative management scenarios. These scenarios include the natural and hydro-social processes and feedback dynamics critical for achieving long-term mitigation of droughts, flooding, and sediment transport. This model is a component of the Flood Flow Connectivity to the Landscape framework, which integrates spatial and hydrologic process models. Scenarios of support and collaboration for land management innovations are simulated to connect flood flow to the floodplains throughout the watershed to replenish soil storage and shallow groundwater aquifers across regional scales. The results reveal the management policy levers and trade-off balances critical for restoring management and water storage capacity to the system for long-term resilience.

Predicting the impact of perennial phases on average leakage from farming systems in south-western Australia

2006 ◽  
Vol 57 (3) ◽  
pp. 269 ◽  
Author(s):  
P. R. Ward
Keyword(s):  
Water Storage ◽  
Farming Systems ◽  
Soil Types ◽  
Buffer Size ◽  
Soil Water Storage ◽  
Annual Rainfall ◽  
Water Storage Capacity ◽  
Modelling Studies ◽  
The Impact

Rising watertables and dryland salinity in southern Australia are due to excess groundwater recharge after the replacement of native vegetation by annual crops and pastures. The inclusion of perennial plants into agricultural systems has been proposed as a possible method of recharge reduction, through the creation of a buffer (extra water storage capacity generated by the perennial in comparison with an annual crop or pasture). However, the role of perennial phases under conditions of highly episodic leakage is not well understood. In this paper, a simple Leakage/Buffer Model (LeBuM) was developed to determine the effect of perennial phases on long-term average annual leakage, incorporating episodic events. Mechanistic modelling studies on contrasting soil types were used to demonstrate that leakage for any given May–December period was directly related to soil water storage at 1 May. From this finding, it follows that leakage from a phase rotation can be calculated if the size of the buffer, and the leakage quantity in the absence of a buffer, are known for each stage of the rotation. LeBuM uses a long-term sequence of leakage values in the absence of a buffer as input, and the maximum buffer size, its rate of development, and the length of perennial and annual phases are specified as parameters. LeBuM was applied to leakage data modelled for 5 contrasting soil types over 100 years at 24 sites in the Western Australian wheatbelt. Phase rotations on duplex, waterlogging duplex, or loamy sand soils reduced leakage by >90% for regions with <380 mm annual rainfall, but were less effective in wetter regions and on deep sands or acid loamy sands. Nevertheless, phase rotations if adopted widely could delay the onset of salinity by as much as several decades.

Vegetation Control in the Long-Term Self-Stabilization of the Liangzhou Oasis of the Upper Shiyang River Watershed of West-Central Gansu, Northwest China

2009 ◽  
Vol 13 (13) ◽  
pp. 1-22 ◽  
Author(s):  
Charles P-A. Bourque ◽  
Quazi K. Hassan
Keyword(s):  
Soil Water ◽  
Land Surface ◽  
Water Storage ◽  
Qilian Mountains ◽  
Soil Water Storage ◽  
River Watershed ◽  
Vegetation Control ◽  
West Central ◽  
The Qilian Mountains

Abstract This paper explores the relationship between vegetation in the Liangzhou Oasis in the Upper Shiyang River watershed (USRW) of west-central Gansu, China, and within-watershed precipitation, soil water storage, and oasis self-support. Oases along the base of the Qilian Mountains receive a significant portion of their water supply (over 90%) from surface and subsurface flow originating from the Qilian Mountains. Investigation of vegetation control on oasis water conditions in the USRW is based on an application of a process model of soil water hydrology. The model is used to simulate long-term soil water content (SWC) in the Liangzhou Oasis as a function of (i) monthly composites of Moderate Resolution Imaging Spectroradiometer (MODIS) images of land surface and mean air temperature, (ii) spatiotemporal calculations of monthly precipitation and relative humidity generated with the assistance of genetic algorithms (GAs), and (iii) a 80-m-resolution digital elevation model (DEM) of the area. Modeled removal of vegetation is shown to affect within-watershed precipitation and soil water storage by reducing the exchange of water vapor from the land surface to the air, increasing the air’s lifting condensation level by promoting drier air conditions, and causing the high-intensity precipitation band in the Qilian Mountains to weaken and to be displaced upward, leading to an overall reduction of water to the Liangzhou Oasis.

Sediment Production in a small Appalachian Watershed during Spring Runoff: The Eaton Basin, 1970–1972

1973 ◽  
Vol 10 (12) ◽  
pp. 1707-1734 ◽  
Author(s):  
M. A. Carson ◽  
C. H. Taylor ◽  
B. J. Grey
Keyword(s):  
United States ◽  
Sediment Transport ◽  
The United States ◽  
Channel Network ◽  
Discharge Data ◽  
Sediment Rating Curve ◽  
Sediment Yields ◽  
Sediment Production ◽  
Spring Runoff

This report describes work in an IHD Representative Basin in the Quebec Appalachians, the Eaton River Basin (86 km2 in area), upstream from Randboro. The Basin is dominantly forest-covered, contains no large settlement, and, in general, shows little human disturbance that might affect sediment production. The suspended load of the Eaton River was studied in detail during the spring runoff periods of 1970 and 1971; available long-term discharge data indicate these to be representative of present-day conditions. Sediment transport rates are well below capacity and sediment yields are lower than might have been expected from the Langbein-Schumm data in the United States. Suspended sediment originates primarily from scour of the banks of the channel network, and concentrations show a systematic increase with basin area (or distance downstream), quite unlike previous data from the midwestern United States. The sediment rating curve approach is a very good predictor of sediment transport rates, although because of the differences in hydrograph type, there is a large difference between the equations for the 1970 and 1971 spring floods. This difference, and residuals from the sediment rating curves, are considered in a simulation model of sediment production from bank erosion based on the changing shear resistance of bank sediment during a fluctuating hydrograph.

scholarly journals A new probability density function for spatial distribution of soil water storage capacity leads to SCS curve number method

2018 ◽  
Author(s):  
Dingbao Wang
Keyword(s):  
Distribution Function ◽  
Storage Capacity ◽  
Water Storage ◽  
Soil Water Storage ◽  
Water Storage Capacity ◽  
Soil Storage ◽  
Soil Water Storage Capacity ◽  
Soil Wetting ◽  
Scs Cn ◽  
New Distribution

Abstract. Following the Budyko framework, soil wetting ratio (the ratio between soil wetting and precipitation) as a function of soil storage index (the ratio between soil wetting capacity and precipitation) is derived from the SCS-CN method and the VIC type of model. For the SCS-CN method, soil wetting ratio approaches one when soil storage index approaches infinity, due to the limitation of the SCS-CN method in which the initial soil moisture condition is not explicitly represented. However, for the VIC type of model, soil wetting ratio equals soil storage index when soil storage index is lower than a certain value, due to the finite upper bound of the power distribution function of storage capacity. In this paper, a new distribution function, supported on a semi-infinite interval x &amp;in; [0, ∞), is proposed for describing the spatial distribution of storage capacity. From this new distribution function, an equation is derived for the relationship between soil wetting ratio and storage index. In the derived equation, soil wetting ratio approaches zero as storage index approaches zero; when storage index tends to infinity, soil wetting ratio approaches a certain value (&amp;leq; 1) depending on the initial storage. Moreover, the derived equation leads to the exact SCS-CN method when initial water storage is zero. Therefore, the new distribution function for soil water storage capacity explains the SCS-CN method as a saturation excess runoff model and unifies the surface runoff modeling of SCS-CN method and VIC type of model.

scholarly journals Diagnosis toward predicting mean annual runoff in ungauged basins

2021 ◽  
Vol 25 (2) ◽  
pp. 945-956
Author(s):  
Yuan Gao ◽  
Lili Yao ◽  
Ni-Bin Chang ◽  
Dingbao Wang
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Storage Capacity ◽  
Water Storage ◽  
Annual Runoff ◽  
Balance Model ◽  
Soil Water Storage ◽  
Ungauged Basins ◽  
Water Storage Capacity ◽  
Soil Water Storage Capacity

Abstract. Prediction of mean annual runoff is of great interest but still poses a challenge in ungauged basins. The present work diagnoses the prediction in mean annual runoff affected by the uncertainty in estimated distribution of soil water storage capacity. Based on a distribution function, a water balance model for estimating mean annual runoff is developed, in which the effects of climate variability and the distribution of soil water storage capacity are explicitly represented. As such, the two parameters in the model have explicit physical meanings, and relationships between the parameters and controlling factors on mean annual runoff are established. The estimated parameters from the existing data of watershed characteristics are applied to 35 watersheds. The results showed that the model could capture 88.2 % of the actual mean annual runoff on average across the study watersheds, indicating that the proposed new water balance model is promising for estimating mean annual runoff in ungauged watersheds. The underestimation of mean annual runoff is mainly caused by the underestimation of the area percentage of low soil water storage capacity due to neglecting the effect of land surface and bedrock topography. Higher spatial variability of soil water storage capacity estimated through the height above the nearest drainage (HAND) and topographic wetness index (TWI) indicated that topography plays a crucial role in determining the actual soil water storage capacity. The performance of mean annual runoff prediction in ungauged basins can be improved by employing better estimation of soil water storage capacity including the effects of soil, topography, and bedrock. It leads to better diagnosis of the data requirement for predicting mean annual runoff in ungauged basins based on a newly developed process-based model finally.

scholarly journals Soil water repellency influences maize yield by changing soil water availability under long-term tillage management

2021 ◽  
Author(s):  
Shengping Li ◽  
Guopeng Liang ◽  
Xueping Wu ◽  
Jinjing Lu ◽  
Erwan Plougonven ◽  
...  
Keyword(s):  
Grain Yield ◽  
Soil Water ◽  
Water Availability ◽  
Water Storage ◽  
Water Repellency ◽  
Conservation Agriculture ◽  
Soil Water Availability ◽  
Soil Water Storage ◽  
Water Sorptivity

Abstract. Drought is increasingly common due to frequent occurrences of extreme weather events, which further increases soil water repellency (SWR) and influences grain yield. Conservation agriculture is playing a vital role in attaining high food security and it could also increase SWR. However, the relationship between SWR and grain yield under conservation agriculture is still not fully understood. We studied the impact of SWR in 0–5 cm, 5–10 cm, and 10–20 cm layers during three growth periods on grain yield from a soil water availability perspective using a long-term field experiment. In particular, we assessed the effect of SWR on soil water content under two rainfall events with different rainfall intensities. Three treatments were conducted: conventional tillage (CT), reduced tillage (RT), and no-tillage (NT). The results showed that the water repellency index (RI) of NT and RT treatments in 0–20 cm layers was increased by 12.9 %–39.9 % and 5.7 %–18.2 % compared to CT treatment during the three growth periods, respectively. The effect of the RI on soil water content became more obvious with the decrease in soil moisture following rainfall, which was also influenced by rainfall intensity. The RI played a prominent role in increasing soil water storage during the three growth periods compared to the soil total porosity, penetration resistance, mean weight diameter, and organic carbon content. Furthermore, although the increment in the RI under NT treatment increased the soil water storage, grain yield was not influenced by RI (p > 0.05) because the grain yield under NT treatment was mainly driven by penetration resistance and least limiting water range (LLWR). The higher water sorptivity increased LLWR and water use efficiency, which further increased the grain yield under RT treatment. Overall, SWR, which was characterized by water sorptivity and RI, had the potential to influence grain yield by changing soil water availability (e.g. LLWR and soil water storage) and RT treatment was the most effective tillage management compared to CT and NT treatments in improving grain yield.

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