scholarly journals Sources and Mechanisms of Low-Flow River Phosphorus Elevations: A Repeated Synoptic Survey Approach

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1497
Author(s):  
Sara E. Vero ◽  
Karen Daly ◽  
Noeleen T. McDonald ◽  
Simon Leach ◽  
Sophie C. Sherriff ◽  
...  
Keyword(s):  
Water Quality Monitoring ◽  
Point Sources ◽  
Low Flow ◽  
Sediment Chemistry ◽  
Water Sampling ◽  
Temperature Conductivity ◽  
Agricultural Catchments ◽  
Oxidation Reduction ◽  
Grassland Diversity ◽  
Reactive Phosphorus

High-resolution water quality monitoring indicates recurring elevation of stream phosphorus concentrations during low-flow periods. These increased concentrations may exceed Water Framework Directive (WFD) environmental quality standards during ecologically sensitive periods. The objective of this research was to identify source, mobilization, and pathway factors controlling in-stream total reactive phosphorus (TRP) concentrations during low-flow periods. Synoptic surveys were conducted in three agricultural catchments during spring, summer, and autumn. Up to 50 water samples were obtained across each watercourse per sampling round. Samples were analysed for TRP and total phosphorus (TP), along with supplementary parameters (temperature, conductivity, dissolved oxygen, and oxidation reduction potential). Bed sediment was analysed at a subset of locations for Mehlich P, Al, Ca, and Fe. The greatest percentages of water sampling points exceeding WFD threshold of 0.035 mg L−1 TRP occurred during summer (57%, 11%, and 71% for well-drained, well-drained arable, and poorly drained grassland catchments, respectively). These percentages declined during autumn but did not return to spring concentrations, as winter flushing had not yet occurred. Different controls were elucidated for each catchment: diffuse transport through groundwater and lack of dilution in the well-drained grassland, in-stream mobilization in the well-drained arable, and a combination of point sources and cumulative loading in the poorly drained grassland. Diversity in controlling factors necessitates investigative protocols beyond low-spatial and temporal resolution water sampling and must incorporate both repeated survey and complementary understanding of sediment chemistry and anthropogenic phosphorus sources. Despite similarities in elevation of P at low-flow, catchments will require custom solutions depending on their typology, and both legislative deadlines and target baselines standards must acknowledge these inherent differences.

scholarly journals Carbon and nutrient export regimes from headwater catchments to downstream reaches

2017 ◽  
Vol 14 (18) ◽  
pp. 4391-4407 ◽  
Author(s):  
Rémi Dupas ◽  
Andreas Musolff ◽  
James W. Jawitz ◽  
P. Suresh C. Rao ◽  
Christoph G. Jäger ◽  
...  
Keyword(s):  
Soluble Reactive Phosphorus ◽  
Point Sources ◽  
Low Flow ◽  
Spatial And Temporal Variability ◽  
River Continuum ◽  
Headwater Catchments ◽  
Freshwater Bodies ◽  
Source Signal ◽  
Reactive Phosphorus ◽  
Stream Transport

Abstract. Excessive amounts of nutrients and dissolved organic matter in freshwater bodies affect aquatic ecosystems. In this study, the spatial and temporal variability in nitrate (NO3−), dissolved organic carbon (DOC) and soluble reactive phosphorus (SRP) was analyzed in the Selke (Germany) river continuum from three headwaters draining 1–3 km2 catchments to two downstream reaches representing spatially integrated signals from 184–456 km2 catchments. Three headwater catchments were selected as archetypes of the main landscape units (land use  ×  lithology) present in the Selke catchment. Export regimes in headwater catchments were interpreted in terms of NO3−, DOC and SRP land-to-stream transfer processes. Headwater signals were subtracted from downstream signals, with the differences interpreted in terms of in-stream processes and contributions from point sources. The seasonal dynamics for NO3− were opposite those of DOC and SRP in all three headwater catchments, and spatial differences also showed NO3− contrasting with DOC and SRP. These dynamics were interpreted as the result of the interplay of hydrological and biogeochemical processes, for which riparian zones were hypothesized to play a determining role. In the two downstream reaches, NO3− was transported almost conservatively, whereas DOC was consumed and produced in the upper and lower river sections, respectively. The natural export regime of SRP in the three headwater catchments mimicked a point-source signal (high SRP during summer low flow), which may lead to overestimation of domestic contributions in the downstream reaches. Monitoring the river continuum from headwaters to downstream reaches proved effective to jointly investigate land-to-stream and in-stream transport, and transformation processes.

Systems view of integrated water quality monitoring within the requirements of the new national water policy in South Africa

1998 ◽  
Vol 38 (11) ◽  
pp. 141-148 ◽  
Author(s):  
P. Marjanovic ◽  
M. Miloradov
Keyword(s):  
South Africa ◽  
Water Quality ◽  
Water Policy ◽  
Systems Approach ◽  
Water Quality Management ◽  
Water Quality Monitoring ◽  
Point Sources ◽  
Quality Monitoring ◽  
Efficient Manner ◽  
National Water

The new National water policy will change the way water quality is managed in South Africa. The paper considers the water policy and the repercussions it will have for water quality monitoring in South Africa. Using the systems approach the paper discusses an integrated water quality monitoring system for ambient water quality and point and non point sources of aquatic pollution. The proposed methodology makes possible continuos assessment of water quality in an efficient manner so as to support water quality management in South Africa.

Statistical and Data Mining Techniques for Understanding Water Quality Profiles in a Mining-Affected River Basin

2018 ◽  
Vol 9 (2) ◽  
pp. 1-19 ◽  
Author(s):  
Jose Simmonds ◽  
Juan A. Gómez ◽  
Agapito Ledezma
Keyword(s):  
Data Mining ◽  
Water Quality ◽  
River Basin ◽  
Suspended Solids ◽  
Water Quality Monitoring ◽  
High Flow ◽  
Quality Monitoring ◽  
Low Flow ◽  
Inverse Relation

This article contains a multivariate analysis (MV), data mining (DM) techniques and water quality index (WQI) metrics which were applied to a water quality dataset from three water quality monitoring stations in the Petaquilla River Basin, Panama, to understand the environmental stress on the river and to assess the feasibility for drinking. Principal Components and Factor Analysis (PCA/FA), indicated that the factors which changed the quality of the water for the two seasons differed. During the low flow season, water quality showed to be influenced by turbidity (NTU) and total suspended solids (TSS). For the high flow season, main changes on water quality were characterized by an inverse relation of NTU and TSS with electrical conductivity (EC) and chlorides (Cl), followed by sources of agricultural pollution. To complement the MV analysis, DM techniques like cluster analysis (CA) and classification (CLA) was applied and to assess the quality of the water for drinking, a WQI.

Water quality modeling in the watershed-based approach for waste load allocations

1998 ◽  
Vol 38 (10) ◽  
pp. 165-172 ◽  
Author(s):  
Ruochuan Gu ◽  
Mei Dong
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Water Quality Modeling ◽  
Point Sources ◽  
Low Flow ◽  
Quality Analysis ◽  
Management Approach ◽  
Water Quality Control ◽  
Quality Modeling ◽  
Waste Load

The conventional method for waste load allocations (WLA) employs spatial-differentiation, considering individual point sources, and temporal-integration, using a constant flow, typically 7Q10 low flow. This paper presents a watershed-based seasonal management approach, in which non-point source as well as point sources are incorporated, seasonal design flows are used for water quality analysis, and WLA are performend in a watershed scale. The strategy for surface water quality modeling in the watershed-based approach is described. The concept of seasonal discharge management is discussed and suggested for the watershed-based approach. A case study using the method for the Des Moines River, Iowa, USA is conducted. Modeling considerations and procedure are presented. The significance of non-point source pollutant load and its impact on water quality of the river is evaluated by analyzing field data. A water quality model is selected and validated against field measurements. The model is applied to projections of future water quality situations under different watershed management and water quality control scenarios with respect to river flow and pollutant loading rate.

scholarly journals Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

2015 ◽  
Vol 19 (1) ◽  
pp. 453-464 ◽  
Author(s):  
J. M. Campbell ◽  
P. Jordan ◽  
J. Arnscheidt
Keyword(s):  
High Resolution ◽  
Water Quality Monitoring ◽  
Low Flow ◽  
Mitigation Measures ◽  
Septic Tank ◽  
Catchment Management ◽  
Soil P ◽  
P Concentration ◽  
Insufficient Time ◽  
Management Advice

Abstract. This study reports the use of high-resolution water quality monitoring to assess the influence of changes in land use management on total phosphorus (TP) transfers in two 5 km2 agricultural sub-catchments. Specifically, the work investigates the issue of agricultural soil P management and subsequent diffuse transfers at high river flows over a 5-year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STSs) and mitigation efforts – a key concern for catchment management. Results showed an inconsistent response to soil P management over 5 years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STSs) and also to gauge their effectiveness.

Simulation of organic carbon loading using MIKE 11 model: a case of River Nzoia, Kenya

2015 ◽  
Vol 10 (2) ◽  
pp. 298-304 ◽  
Author(s):  
Edwin K. Kanda ◽  
Job R. Kosgei ◽  
Emmanuel C. Kipkorir
Keyword(s):  
Lake Victoria ◽  
Agricultural Runoff ◽  
Point Sources ◽  
Low Flow ◽  
Quality Data ◽  
Coefficient Of Determination ◽  
Lake Victoria Basin ◽  
Water Quality Data ◽  
Mike 11 ◽  
Mike 11 Model

River Nzoia is the largest river draining into the Kenyan portion of Lake Victoria. This river receives both point sources of pollution from industrial and municipal wastes, and non-point sources from agricultural runoff in the catchment. The objective of this study was to simulate dissolved oxygen (DO) and biochemical oxygen demand (BOD) of the middle section of River Nzoia using MIKE 11 model. The model was calibrated using discharge and water quality data for 2009 and validated with March–April 2013 data. The model performance was good with coefficient of determination (R2) values of between 0.845 and 0.995, Nash–Sutcliffe efficiency values of between 0.748 and 0.993 and percent bias of less than 10 for both calibration and validation of electrical conductivity (EC), DO and BOD. EC and BOD values were lower for April compared to March which could be attributed to dilution during high flows. DO values were above the recommended minimum level of 4 mg/l in all the sections of the river in the wet period but some sections had lower than 4 mg/l during low flow period. The government agencies such as Water Resources Management Authority and National Environment Management Authority should enforce the effluent standards to ensure that industries and wastewater treatment plants adhere to the maximum allowable limit for BOD and also improve their treatment efficiencies of wastewater plants so as to improve the quality of River Nzoia which is important in the overall management of the Lake Victoria basin.

Systems approach to effective water quality management in the Republic of South Africa, existing situation and expected future developments

1998 ◽  
Vol 38 (11) ◽  
pp. 77-85
Author(s):  
P. Marjanovic ◽  
M. Miloradov ◽  
F. van Zyl
Keyword(s):  
South Africa ◽  
Water Quality ◽  
Quality Management ◽  
Water Policy ◽  
Systems Approach ◽  
Water Quality Management ◽  
Water Quality Monitoring ◽  
Point Sources ◽  
Sources Of Pollution ◽  
Management Functions

The new National water policy will change the way water quality is managed in South Africa. The paper considers the water policy and the repercussions it will have for water quality management in South Africa and proposes a system that can be used to come up with optimum solutions for water quality management. The proposed solution integrates policy and institutional arrangements with the Cadastral system for point and non point sources of pollution and optimisation tools to ensure optimal management of water quality at any given time. The water quality management functions catered for by the proposed system are: resource allocation for pollution discharge, water quality protection, water quality monitoring, planning, development and operation.

Sensitivity analysis of non-point sources in a water quality model applied to a dammed low-flow-reach river

2008 ◽  
Vol 57 (8) ◽  
pp. 1295-1300
Author(s):  
Nayana G. M. Silva ◽  
Marcos von Sperling
Keyword(s):  
Water Quality ◽  
Sensitivity Analysis ◽  
Initial Conditions ◽  
Quality Parameters ◽  
Water Quality Model ◽  
Point Sources ◽  
Low Flow ◽  
Treated Wastewater ◽  
Quality Model ◽  
River Bed

Downstream of Capim Branco I hydroelectric dam (Minas Gerais state, Brazil), there is the need of keeping a minimum flow of 7 m3/s. This low flow reach (LFR) has a length of 9 km. In order to raise the water level in the low flow reach, the construction of intermediate dikes along the river bed was decided. The LFR has a tributary that receives the discharge of treated wastewater. As part of this study, water quality of the low-flow reach was modelled, in order to gain insight into its possible behaviour under different scenarios (without and with intermediate dikes). QUAL2E equations were implemented in FORTRAN code. The model takes into account point-source pollution and diffuse pollution. Uncertainty analysis was performed, presenting probabilistic results and allowing identification of the more important coefficients in the LFR water-quality model. The simulated results indicate, in general, very good conditions for most of the water quality parameters The variables of more influence found in the sensitivity analysis were the conversion coefficients (without and with dikes), the initial conditions in the reach (without dikes), the non-point incremental contributions (without dikes) and the hydraulic characteristics of the reach (with dikes).

Towards experimentally-based environmental flows for infrastructure management in high-altitude tropical streams

2020 ◽  
Author(s):  
Daniela Rosero-Lopez
Keyword(s):  
High Altitude ◽  
Environmental Flows ◽  
Benthic Fauna ◽  
Benthic Algae ◽  
Tropical Streams ◽  
Low Flow ◽  
Infrastructure Management ◽  
Temperature Conductivity ◽  
Stream Morphology ◽  
Flow Deviation

<p>Thresholds from flow–benthic fauna relationships in the light of data-scarce hydrosystems constitute an advance in implementing sustainable principles for water infrastructure management. To quantify thresholds the limits to the amount of water that can be withdrawn from Andean river networks before their natural functioning, biodiversity and ecosystem services become degraded, we conducted a whole-ecosystem experimental flow alteration. We reduced flow in the reach of a stream above a water intake from the supply system for the city of Quito, Ecuador. During the low-flow season, we diverted water using a system of weirs to accommodate streamflow in complementary percent (i.e., 90% flow deviation and 10% flow left in the stream). We performed seven reductions and kept them for seven days, during that time we sampled benthic algae chlorophyll-a concentration, flow, temperature, conductivity, light, and measured stream morphology. Our preliminary results indicate a high variability of ecological and physical responses to hydrological alterations in high-altitude tropical streams. A reduction to minimum flow similar to conditions observed for low-flows caused significant changes in stream morphology, and reductions above this threshold evidenced changes in the relative presence of major benthic algae groups.</p>

Sign in / Sign up

Export Citation Format

Share Document