Cycle of pre-drought, drought, and recovery of “green” and “blue” water fluxes and soil water ages of grassland and forested sites.

This study describes a laboratory and field-based assessment of the performance of suspended sediment monitoring techniques commonly used in gullies. We also evaluate a recently-described method; the pumped active suspended sediment sampler, which has been modified for monitoring suspended sediment in gully systems. The methods evaluated were influenced by fluvial processes that were exacerbated by the sediment dynamics of gullies (e.g., rapid vertical movement of the channel bed during flow events) or sampling bias (e.g., underestimation suspended sand concentration).

In snowmelt-dominated river systems, groundwater plays a key role in maintaining base flow during dry periods. Karst groundwater systems, when present, play a large role in delaying discharge to the rivers. Even when these karst systems are spatially limited, river base-flow behaviours can best be explained by the amount of karst present in the river basin.

1. Incorporating SMP in the lumped conceptual SCS-CN based sediment yield.
2. We develop SMP-based sediment yield models (SMPSY) by coupling the Ia-λ model, and SMA concept.
3. The SMPSY models incorporate watershed storage index (S) to avoid sudden jump in sediment yield computations.

We develop Soil Moisture Proxies (SMP) based suspended sediment yield (SMPSY) models corresponding to three AMCs (i.e., AMC-I-AMC-III) for modelling rainfall generated suspended sediment yield by coupling the improved initial abstraction (Ia-λ) relationship and SMA procedure. The SMPSY models incorporate watershed storage index (S) to avoid the sudden jumps in sediment yield computations. We found that the characterization of soil moisture variability in terms of SMPs and improved Ia-λ relationship with SMA improves the simulation of the sediment yield generation process.

Hydrographs similarity and hysteresis indicates that the aquifer types, storage and permeability control hydrological function across the “hillslope–depression–stream” continuum in a karst catchment. When depression storage deficits are filled during consecutive rainfall events, depression hydrographs at the high permeability sites are almost synchronous or exhibit a monotonous function with the hydrographs at the outlet. Preferential flow paths in fractured rocks and conduits enhance flow connectivity between hillslopes and the out, propagating pressure wave over longer distances.

• At watershed-scale, geostatistical analysis shows that using the geometric means of the 10 sites performs better than using either all the K_v values from the 93 permeameter tests or 10 K_v values from the middle transects and centre permeameters
• Within channel bends, higher spatial variability in streambed K_v was observed across stream channels than along stream channels.
• Meandering channels showed a more heterogeneous distribution of streambed K_v when compared to straight channels.

The H-O isotopic values of soil water and plant water varied greatly with season. Mature plants gained deep soil water but young plant did not in the warm-wet period. Young plants got surface soil water but mature plants did not in the cold-dry period. Plant types did not affect water uptake patterns for mature plants.

Stable isotopes of water (δ²H and δ¹⁸O) provide information on the water source and the hydrological processes that affect it as it moves through the hydrosphere. Here, we developed the first isoscape of groundwater δ²H and δ¹⁸O for the conterminous United States based on a random forest model using environmental variables as predictors (figure). We also calculated the seasonal recharge efficiency and proportion for several 1000 locations and used these results to make inferences on the hydrologic and environmental processes that affect groundwater systems across the United States.

This study applied multiple water quality analyses to investigate transient changes in groundwater recharge sources in response to river turbidity caused by a large landslide in 2015. Mixing ratios of the river water with groundwater samples near the river, estimated by a two-endmember mixing model based on strontium isotope and concentration, decreased along the left bank and in the middle stream area during 2016.

• Naturally regenerating cloud forests promote hydrologic services compared to that of mature forest (MF).
• Forty years of intense pasture management was found to have degraded the soil hydraulic properties of IP; reducing its infiltration capacity, causing a fivefold greater peak flow response and a lower baseflow compared to MF.
• Shade coffee (SC) alternatives exhibited a high capacity to modulate peak flows comparable to that of MF and an intermediate capacity to sustain baseflow.

Many investigators have attempted to define the threshold of landslide failure, that is, the level of the selected climatic variable above which a rainfall-induced landslide occurs. The relationship between rainfall duration and kinetic power corresponding to landslides triggered by rain was used to propose a new approach to define the threshold for predicting landslide occurrence. This new method can be applied using commonly applied relationship for estimating the kinetic power per unit volume of rainfall and a new equation based on the measured raindrop size distribution.