scholarly journals Quantifying the differential contributions of deep groundwater to streamflow in nested basins, using both water quality characteristics and water balance

2013 ◽  
Vol 45 (2) ◽  
pp. 200-212 ◽  
Author(s):  
M. C. Ockenden ◽  
N. A. Chappell ◽  
C. Neal
Keyword(s):  
Water Budget ◽  
Quality Characteristics ◽  
Mixing Model ◽  
Rainfall Runoff ◽  
Bicarbonate Concentration ◽  
Deep Groundwater ◽  
Two Component ◽  
End Members ◽  
Chemical Mixing ◽  
High Storage

This paper describes use of a hydro-chemical mixing model and a water budget to investigate the presence of deep runoff pathways in two small, nested sub-catchments of the Eden basin, UK (8.8 km2 Blind Beck and 1.0 km2 Low Hall stream). A linear relationship between bicarbonate concentration and electrical conductivity was used in a two-component mixing model. End-members were identified as a high-solute, deep groundwater and a low-solute, soil-water. The mixing model indicated 69% ± 10% deep groundwater in Low Hall for September–December 2008 and 46% ± 8% in Blind Beck for the same period. The water budget also indicated more deep groundwater in Low Hall stream. These results were consistent with the findings of rainfall–runoff models which also indicated the presence of high storage, deeper pathways.

scholarly journals A hydrochemical modelling framework for combined assessment of spatial and temporal variability in stream chemistry: application to Plynlimon, Wales

2001 ◽  
Vol 5 (1) ◽  
pp. 49-58 ◽  
Author(s):  
H.J. Foster ◽  
M.J. Lees ◽  
H.S. Wheater ◽  
C. Neal ◽  
B. Reynolds
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Spatial Variability ◽  
Temporal Variability ◽  
Biological Diversity ◽  
Spatial And Temporal Variability ◽  
Stream Chemistry ◽  
Two Component ◽  
End Members

Abstract. Recent concern about the risk to biota from acidification in upland areas, due to air pollution and land-use change (such as the planting of coniferous forests), has generated a need to model catchment hydro-chemistry to assess environmental risk and define protection strategies. Previous approaches have tended to concentrate on quantifying either spatial variability at a regional scale or temporal variability at a given location. However, to protect biota from ‘acid episodes’, an assessment of both temporal and spatial variability of stream chemistry is required at a catchment scale. In addition, quantification of temporal variability needs to represent both episodic event response and long term variability caused by deposition and/or land-use change. Both spatial and temporal variability in streamwater chemistry are considered in a new modelling methodology based on application to the Plynlimon catchments, central Wales. A two-component End-Member Mixing Analysis (EMMA) is used whereby low and high flow chemistry are taken to represent ‘groundwater’ and ‘soil water’ end-members. The conventional EMMA method is extended to incorporate spatial variability in the two end-members across the catchments by quantifying the Acid Neutralisation Capacity (ANC) of each in terms of a statistical distribution. These are then input as stochastic variables to a two-component mixing model, thereby accounting for variability of ANC both spatially and temporally. The model is coupled to a long-term acidification model (MAGIC) to predict the evolution of the end members and, hence, the response to future scenarios. The results can be plotted as a function of time and space, which enables better assessment of the likely effects of pollution deposition or land-use changes in the future on the stream chemistry than current methods which use catchment average values. The model is also a useful basis for further research into linkage between hydrochemistry and intra-catchment biological diversity. Keywords: hydrochemistry, End-Member Mixing Analysis (EMMA), uplands, acidification

THE DISTRIBUTION OF THE RED AND YELLOW COLOURS OF THE MUSCLE TISSUE OF BRITISH COLUMBIA CANNED SPRING SALMON AROUND THE MEANS OF THE INDIVIDUAL DISTRIBUTIONS OCCURRING IN SMALL, ARBITRARILY CHOSEN TIME INTERVALS

1940 ◽  
Vol 18d (12) ◽  
pp. 410-422
Author(s):  
F. Charnley ◽  
Laura M. Harcus
Keyword(s):  
British Columbia ◽  
Muscle Tissue ◽  
Quality Characteristics ◽  
Complete Agreement ◽  
Time Intervals ◽  
Normal Distributions ◽  
Two Component ◽  
The Individual

The distributions of the red and yellow colours of the cooked muscle tissue of British Columbia spring salmon (Oncorhynchus Tschawytscha) around the means of the individual distributions occurring in small, arbitrarily chosen time intervals are composite distributions each consisting of two component normal distributions, thus indicating that there are two, and only two, varieties of this species when the salmon are classified on the basis of these two quality characteristics. The proportions of the pale and red varieties are very nearly 1:3 so that when sampling fluctuations are taken into account the data are in complete agreement with the hypothesis that the true proportions are, respectively, [Formula: see text] and [Formula: see text].

scholarly journals Subsurface lateral flow from hillslope and its contribution to nitrate loading in the streams during typical storm events in an agricultural catchment

2011 ◽  
Vol 8 (2) ◽  
pp. 4151-4193 ◽  
Author(s):  
J. Tang ◽  
B. Zhang ◽  
C. Gao ◽  
H. Zepp
Keyword(s):  
Surface Water ◽  
Soil Water ◽  
Stream Flow ◽  
Mixing Model ◽  
Lateral Flow ◽  
Storm Events ◽  
N Loss ◽  
Total N ◽  
Subsurface Lateral Flow ◽  
Chemical Mixing

Abstract. Compared with overland flow from agricultural hillslopes, subsurface lateral flow is often overlooked partly due to monitoring difficulties and the lack of quantitative identification its role in nutrient delivery to surface water. The objectives of this study were to examine how subsurface lateral flow generates from hillslopes to streams and to quantify its contribution to nutrient loading in streams. Hillslope hydrology and stream hydrology were simultaneously monitored during two typical storms and subsurface flow was separated by chemical mixing model. Positive soil water potential at the soil depths from 0.60 to 1.50 m was observed at the middle course of the storm events, suggesting soil water was saturated following the storms and the drained after the end of the storms. The hydro-chemographs in the stream in a trench below a hillslope showed that suspended sediment, particulate N and P were dominant in the stream during the storms, while after the end of the rainstorms the nitrate concentration and electricity conductivity (EC) in the stream increased with time on the recession limbs of the hydrographs. Meanwhile, a rebound or delayed curve appeared on the recession limbs for several hours immediately after the end of rainstorms. All the synchronous data confirmed nitrate was delivered from the hillslope through subsurface lateral flow to the streams even after the end of rainstorms. A chemical mixing model based on EC and pH showed that the subsurface lateral flow during the rainstorm events accounted for 29% to 45% of the stream flow and about 86% of total NO3−-N loss (or 26% of total N loss) from the peanut hillslope and for 5.7% to 7.3% of the stream flow about 69% of total NO3−-N loss (or 28% of total N loss) from the catchment outlet. The results suggest that subsurface lateral flow generated within a shallow soil profile have to be paid more attention for controlling non-point source surface water pollution from intensive agricultural catchment.

scholarly journals Hydro-Geomorphologic-Based Water Budget at Event Time-Scale in A Mediterranean Headwater Catchment (Southern Italy)

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 20
Author(s):  
Albina Cuomo ◽  
Domenico Guida
Keyword(s):  
Water Budget ◽  
Goodness Of Fit ◽  
Southern Italy ◽  
Interdisciplinary Approach ◽  
Rainfall Runoff ◽  
Ungauged Catchments ◽  
Campania Region ◽  
Storage Coefficient ◽  
Event Time ◽  
Object Based

The Ciciriello catchment is a 3 km2 drainage sub-basin of the Bussento river basin, located in the southern part of the Campania Region (Southern Italy). Since 2012, this catchment has been studied using an interdisciplinary approach—geomorphological, hydrogeological, and hydrological—and a hydro-chemical monitoring system. Following previous research, the aim of this paper is to calibrate, on this catchment, the hydrologic parameters for a water budget at event time-scales using the HEC-HMS model, adopting object-based hydro-geomorphological class features. Firstly, lumped modeling was performed to calibrate the hydrologic parameters from 20 observed hydrographs at the downstream monitoring station of the Ciciriello catchment. Then, physical-based rainfall–runoff modeling was conducted using three different procedures: (1) applying the recession coefficients to each outlet with a newly defined hydro-geomorphologic index (HGmI); (2) assessing the storage coefficient for each sub-basin as a weighted mean of HGmI; and (3) using the storage coefficient associated with the largest HGmI in the sub-basin. The adopted procedures were tested using diverse goodness-of-fit indices, resulting in good performance when the object-based hydro-geomorphotypes were used for the parameter calibration. The adopted procedure can thus contribute to improvements in rainfall–runoff and water budget modeling in similar ungauged catchments in Mediterranean, hilly, and forested landscapes.

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