Past and future sustainability of water policies in Europe

The article contributes to a discussion on two global issues on water: water resources management, and water supply and sanitation. Focusing on Europe, it traces the legal roots of current systems in history: as a resource, water is considered as a common property, rather than a market good; while as a public service it is usually a commodity. Public water supply and sanitation technologies and engineering have developed under three main paradigms: quantitative and civil engineering; qualitative and chemical/sanitary engineering (both on the supply side); and the most recent one, environmental engineering and integrated management (on the demand side). The cost of public drinking water is due to rise sharply in view of the two‐fold financial challenge of replacing an ageing infrastructure and keeping up with ever‐rising environmental and sanitary quality standards. Who will pay? Government subsidies, or water users? The author suggests that apparent successes with privatisation may have relied heavily on hidden government subsidies and/or the healthy state of previously installed water infrastructure: past government subsidies are still felt for as long as the lifetime of the infrastructure. The article stresses the importance of public participation and decentralized local management of water and sanitation services. Informing and involving users in water management decisions is seen as an integral part of the ‘ethics’ side of the crucial three E's (economics, environment, ethics). The article strongly argues for municipal provision of water services, and hopes that lessons learnt and solutions found in the European experience may serve water services management efforts in other regions of the world.     

Modeling of Vertical Solute Dispersion in a Sediment Bed Enhanced by Wave‐Induced Interstitial Flow1

Abstract: Mass (solute) transport in a stream or lake sediment bed has a significant effect on chemical mass balances and microbial activities in the sediment. A “1D vertical dispersion model” is a useful tool to analyze or model solute transfer between river or lake water and a sediment bed. Under a motionless water column, solute transfer into and within the sediment bed is by molecular diffusion. However, surface waves or bed forms create periodic pressure waves along the sediment/water interface, which in turn induce flows in the pores of the sediment bed. The enhancement of solute transport by these interstitial periodic flows in the pores has been incorporated in a 1D depth‐dependent “enhanced dispersion coefficient (D_E).” Typically, D_E diminishes exponentially with depth in the sediment bed. Relationships have been developed to estimate D_E as a function of the characteristics of sediment (particle size, hydraulic conductivity, and porosity) and pressure waves (wave length and height). In this paper, we outline and illustrate the calculation of D_E as well as the penetration depth (d_p) of the flow effect. Sample applications to illustrate the computational procedure are provided for dissolved oxygen transfer into a stream gravel bed and release of phosphorus from a lake bed. The sensitivity of the results to input parameter values is illustrated, and compared with the errors obtained when interstitial flow is ignored. Maximum values of D_E near the sediment surface can be on the order of 1 cm²/s in a stream gravel bed with standing waves, and 0.001 cm²/s in a fine sand lake bed under progressive surface waves, much larger than molecular diffusion coefficients.     

A Regional Modeling Framework of Phosphorus Sources and Transport in Streams of the Southeastern United States1

García, Ana María, Anne B. Hoos, and Silvia Terziotti, 2011. A Regional Modeling Framework of Phosphorus Sources and Transport in Streams of the Southeastern United States. Journal of the American Water Resources Association (JAWRA) 47(5):991‐1010. DOI: 10.1111/j.1752‐1688.2010.00517.x Abstract: We applied the SPARROW model to estimate phosphorus transport from catchments to stream reaches and subsequent delivery to major receiving water bodies in the Southeastern United States (U.S.). We show that six source variables and five land‐to‐water transport variables are significant (p < 0.05) in explaining 67% of the variability in long‐term log‐transformed mean annual phosphorus yields. Three land‐to‐water variables are a subset of landscape characteristics that have been used as transport factors in phosphorus indices developed by state agencies and are identified through experimental research as influencing land‐to‐water phosphorus transport at field and plot scales. Two land‐to‐water variables – soil organic matter and soil pH – are associated with phosphorus sorption, a significant finding given that most state‐developed phosphorus indices do not explicitly contain variables for sorption processes. Our findings for Southeastern U.S. streams emphasize the importance of accounting for phosphorus present in the soil profile to predict attainable instream water quality. Regional estimates of phosphorus associated with soil‐parent rock were highly significant in explaining instream phosphorus yield variability. Model predictions associate 31% of phosphorus delivered to receiving water bodies to geology and the highest total phosphorus yields in the Southeast were catchments with already high background levels that have been impacted by human activity.     

Seasonal Flushing of Pollutant Concentrations and Loads in Urban Stormwater1

Schiff, Kenneth C. and Liesl L. Tiefenthaler, 2011. Seasonal Flushing of Pollutant Concentrations and Loads in Urban Stormwater. Journal of the American Water Resources Association (JAWRA) 47(1):136‐142. DOI: 10.1111/j.1752‐1688.2010.00497.x Abstract: Despite broad observations of first flush within storms, the scientific understanding of seasonal flushing remains incomplete. Seasonal flushing occurs when initial storms of the season have greater concentrations or loads than storms later in the season. The goal of this study was to census stormwater concentrations and loads from an arid, urban watershed to quantify seasonal flushing. Samples were collected every 15 min during the 1997‐1998 wet season from the Santa Ana River and analyzed for total suspended solids. Initial storms of the season generated event mean concentrations 3‐10 times the event mean concentration of storms later in the season. Cumulative flow‐weighted mean concentrations were calculated as the season progressed. Early season storms discharged only 6% of the annual volume, but influenced flow‐weighted mean concentrations well past the midpoint of the wet season. Mass‐based estimates also indicated a disproportionate load in the early portion of the year; over 52% of the annual load was discharged in the first 30% of the annual volume from the highly urbanized lower watershed. Other stormwater pollutants, including six trace metals (Cd, Cr, Cu, Pb, Ni, Zn), were highly correlated with total suspended solids and also exhibited a significant seasonal flush.     

Source and Delivery of Nutrients to Receiving Waters in the Northeastern and Mid‐Atlantic Regions of the United States1

Moore, Richard B., Craig M. Johnston, Richard A. Smith, and Bryan Milstead, 2011. Source and Delivery of Nutrients to Receiving Waters in the Northeastern and Mid‐Atlantic Regions of the United States. Journal of the American Water Resources Association (JAWRA) 47(5):965‐990. DOI: 10.1111/j.1752‐1688.2011.00582.x Abstract: This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water‐resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid‐Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake.     

Sources of Suspended-Sediment Flux in Streams of the Chesapeake Bay Watershed: A Regional Application of the SPARROW Model1

Brakebill, John W., Scott W. Ator, and Gregory E. Schwarz, 2010. Sources of Suspended-Sediment Flux in Streams of the Chesapeake Bay Watershed: A Regional Application of the SPARROW Model. Journal of the American Water Resources Association (JAWRA) 46(4): 757-776. DOI: 10.1111/j.1752-1688.2010.00450.x Abstract: We describe the sources and transport of fluvial suspended sediment in nontidal streams of the Chesapeake Bay watershed and vicinity. We applied SPAtially Referenced Regressions on Watershed attributes, which spatially correlates estimated mean annual flux of suspended sediment in nontidal streams with sources of suspended sediment and transport factors. According to our model, urban development generates on average the greatest amount of suspended sediment per unit area (3,928 Mg/km²/year), although agriculture is much more widespread and is the greatest overall source of suspended sediment (57 Mg/km²/year). Factors affecting sediment transport from uplands to streams include mean basin slope, reservoirs, physiography, and soil permeability. On average, 59% of upland suspended sediment generated is temporarily stored along large rivers draining the Coastal Plain or in reservoirs throughout the watershed. Applying erosion and sediment controls from agriculture and urban development in areas of the northern Piedmont close to the upper Bay, where the combined effects of watershed characteristics on sediment transport have the greatest influence may be most helpful in mitigating sedimentation in the bay and its tributaries. Stream restoration efforts addressing floodplain and bank stabilization and incision may be more effective in smaller, headwater streams outside of the Coastal Plain.     

Hot Spots and Hot Moments in Riparian Zones: Potential for Improved Water Quality Management1

Vidon, Philippe, Craig Allan, Douglas Burns, Tim P. Duval, Noel Gurwick, Shreeram Inamdar, Richard Lowrance, Judy Okay, Durelle Scott, and Steve Sebestyen, 2010. Hot Spots and Hot Moments in Riparian Zones: Potential for Improved Water Quality Management. Journal of the American Water Resources Association (JAWRA) 46(2):278-298. DOI: 10.1111/j.1752-1688.2010.00420.x Abstract: Biogeochemical and hydrological processes in riparian zones regulate contaminant movement to receiving waters and often mitigate the impact of upland sources of contaminants on water quality. These heterogeneous processes have recently been conceptualized as “hot spots and moments” of retention, degradation, or production. Nevertheless, studies investigating the importance of hot phenomena (spots and moments) in riparian zones have thus far largely focused on nitrogen (N) despite compelling evidence that a variety of elements, chemicals, and particulate contaminant cycles are subject to the influence of both biogeochemical and transport hot spots and moments. In addition to N, this review summarizes current knowledge for phosphorus, organic matter, pesticides, and mercury across riparian zones, identifies variables controlling the occurrence and magnitude of hot phenomena in riparian zones for these contaminants, and discusses the implications for riparian zone management of recognizing the importance of hot phenomena in annual solute budgets at the watershed scale. Examples are presented to show that biogeochemical process-driven hot spots and moments occur along the stream/riparian zone/upland interface for a wide variety of constituents. A basic understanding of the possible co-occurrence of hot spots and moments for a variety of contaminants in riparian systems will increase our understanding of the influence of riparian zones on water quality and guide management strategies to enhance nutrient or pollutant removal at the landscape scale.     

Resolution and Analysis of Spatial Variations and Patterns in an Urban Lake with Rapid Profiling Instrumentation

Rapid response vertical profiling instrumentation was used to document spatial variability and patterns in a small urban lake, Onondaga Lake, associated with multiple drivers. Paired profiles of temperature, specific conductance (SC), turbidity (T_n), fluorometric chlorophyll a (Chl_f), and nitrate nitrogen (NO₃^?) were collected at >30 fixed locations (a “gridding”) weekly, over the spring to fall interval of several years. These gridding data are analyzed (1) to characterize phytoplankton (Chl_f) patchiness in the lake's upper waters, (2) to establish the representativeness of a single long‐term site for monitoring lake‐wide conditions, and (3) to resolve spatial patterns of multiple tracers imparted by buoyancy effects of inflows. Multiple buoyancy signatures were resolved, including overflows from less dense inflows, and interflows to metalimnetic depths and underflows to the bottom from the plunging of more dense inputs. Three different metrics had utility as tracers in depicting the buoyancy signatures as follows: (1) SC, for salinity‐enriched tributaries and the more dilute river that receives the lake's outflow, (2) T_n, for the tributaries during runoff events, and (3) NO₃^?, for the effluent of a domestic waste treatment facility and from the addition of NO₃^? solution to control methyl mercury. The plunging inflow phenomenon, which frequently prevailed, has important management implications.     

Observations and Modeling of Stream Plunging in an Urban Lake1

Owens, Emmet M., Steven W. Effler, Anthony R. Prestigiacomo, David A. Matthews, and Susan M. O’Donnell, 2012. Observations and Modeling of Stream Plunging in an Urban Lake. Journal of the American Water Resources Association (JAWRA) 48(4): 707‐721. DOI: 10.1111/j.1752‐1688.2012.00646.x Abstract: The plunging behavior of two tributaries in Onondaga Lake, New York, is quantified based on a program of monitoring, process studies, and modeling. The dynamics of buoyancy of the tributaries are resolved with hourly measurements of temperature (T), specific conductance (SC), and turbidity (Tn) at the mouths, and observations every 6 h in the lake. Negative buoyancy of the tributaries is found to diminish and change rapidly during runoff events compared to dry periods. In‐lake patterns of the transport of plunging inflow are resolved for dry weather conditions using a dye tracer, and following a runoff event through measurements of T, SC, and Tn. The hydrodynamic/transport model ELCOM (Estuary Lake and Coastal Ocean Model) is demonstrated to perform well in simulating these patterns. Analyses conducted with the model establish the importance of diurnal effects and in‐lake mixing mediated by wind, the need for temporally detailed measurements during runoff events, and modifications of the plunging behavior of the urban tributary as it passes through a harbor. The model provides critical information to support rehabilitation programs for the lake by quantifying the transport of the two largest tributaries, particularly the distribution of the loads between the upper waters and stratified layers. The model predicts that 10% of the urban tributary load enters the upper waters of the lake within 24 h for a dry weather period; this portion increases to 30% for a runoff event.     

Sources and Transport of Phosphorus to Rivers in California and Adjacent States,U.S., as Determined by SPARROW Modeling

The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de‐trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small‐ and intermediate‐sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.     

Modeling the Highly Dynamic Loading of Mercury Species in the Carson River and Lahontan Reservoir System,Nevada

The semiarid Carson River — Lahontan Reservoir system in Nevada, United States is highly contaminated with mercury (Hg) from historic mining with contamination dispersed throughout channel and floodplain deposits. Work builds on previous research using a fully dynamic numerical model to outline a complete conceptualization of the system that includes transport and fate of both sorbed and dissolved constituents. Flow regimes are defined to capture significant mechanisms of Hg loading that include diffusion, channel pore water advective flux, bank erosion, and overbank deposition. Advective flux of pore water is required to reduce dilution and likely represents colloidal‐mediated transport. Fluvial concentrations span several orders of magnitude with spatial and temporal trends simulated within 10‐24% error for all modeled species. Over the simulation period, 1991‐2008, simulated loads are 582 kg/yr (THg²⁺), 4.72 kg/yr (DHg²⁺), 0.54 kg/yr (TMeHg), and 0.07 kg/yr (DMeHg) with bank erosion processes the principal mechanism of loading for both total and dissolved species. Prediction error in the reservoir is within one‐order of magnitude and considered qualitative; however, simulated results indicate internal cycling within the receiving reservoir accounts for only 1% of the reservoir's water column contamination, with river channel sediment sources more influential in the upper reservoir and bank erosion processes having greater influence in the lower reservoir.     

Role of Riparian Areas in Atmospheric Pesticide Deposition and Its Potential Effect on Water Quality

Riparian buffers are known to mitigate hydrologic losses of nutrients and other contaminants as they exit agricultural fields. The vegetation of riparian buffers can also trap atmospheric contaminants, and these pollutants can subsequently be delivered via rain to the riparian buffer floor. These processes, however, are poorly understood especially for pesticide residues. Therefore, we conducted a four‐year study examining stemflow and throughfall to a riparian buffer which was adjacent a cultured Zea mays field treated with atrazine and metolachlor. Stemflow is rain contacting the tree canopy traveling down smaller to larger branches and down the tree trunk, whereas throughfall is rain that may or may not contact leaves and branches and reaches the earth. Stemflow concentrations of the herbicides were larger than throughfall concentrations and accounted for 5‐15% of the atrazine and 6‐66% of the metolachlor depositional fluxes under the canopy. Larger depositional fluxes were measured when leaves were more fully emerged and temperatures and humidity were elevated. Rain collected outside the riparian buffer on the field side and on the back side revealed the trees trapped the herbicide residues. Herbicide loading to the riparian buffer stream was found to be linked to tree canopy deposition and subsequent washoff during rain events. These results indicate that in agricultural areas canopy washoff can be an important source of pesticides to surface waters.     

Water injustices and potential remedies in indigenous rural contexts: A water justice analysis

This paper examines Indigenous water rights in rural and remote Australia and how water justice seems to be elusive in many of these spaces. The purpose of this literature review is to link water justice theory and practices to the way different water cultures are valued in Australia while simultaneously critiquing the water justice movement. This paper situates the notion of water justice as a specific kind of environmental justice to cater for the unique qualities that define this resource. In doing so, this paper draws on Schlosberg’s (2004) conception of environmental justice with its trivalent approach that describes the following three ‘circles of concern’: recognition of difference, plurality of participation, and finally equitable distribution of resources and costs and benefits. This framework provides that if the first two ‘circles of concern’ are not in existence in a natural resource management process, then inequitable distribution of that resource is a likely outcome. This paper presents two areas where water injustices exist in the context of Indigenous rural and remote Australia. The first relates to how Indigenous rights to water have been inadequately recognized and the second presents empirical data on water supply and sanitation in rural and remote Indigenous communities that demonstrates ongoing dilemmas around securing this basic human right. The undervaluing of cultural differences relating to water is argued to be antecedent to the injustice manifest in poor water supply and sanitation provision for Indigenous rural contexts. This paper does not attempt to survey the body of ethnographic work on society-water relations in rural and remote Indigenous Australian contexts but reviews the gaps in current mainstream acknowledgement of Indigenous water cultures. In exploring water justice in rural and remote Indigenous Australia, this paper offers a novel approach to a dilemma more frequently analysed solely as a health development issue.     

A screening model for fate and transport of biodegradable polyesters in soil

A numerical model for predicting the fate and transport of biodegradable polyester residues in soil, following successive applications of mulch film, was developed and applied. The polymer, applied on surface soil, was assumed to be converted into by-products (monomers), according to a first order kinetics with constant K(1deg). The monomers released were assumed to sorb on soil organic matter (according to a first-order kinetics with constant K(s)), to be leached with the seepage water, through vertical advection and hydrodynamic dispersion, and biodegraded (according to a first-order kinetics with constant K(b)). Results suggested that, to assess a possible build-up of mulch film (as a polymer) on the surface soil, the degradation constant K(1deg) relating the polymer conversion to by-products should be known, whereas the biodegradation constant K(b) indicates there is no danger of groundwater pollution. Likewise, on the basis of by-product concentration in deep soil, soil pollution should not occur.     

Degradation of polycyclic aromatic hydrocarbons by combined chemical pre-oxidation and bioremediation in creosote contaminated soil

The ability of pre-oxidation to overcome polycyclic aromatic hydrocarbons (PAH) recalcitrance to biodegradation was investigated in creosote contaminated soil. Sand and peat artificially spiked with creosote (quality WEI C) were used as model systems. Ozonation and Fenton-like treatment were proved to be feasible technologies for PAH degradation in soil. The efficiency of ozonation was strongly dependent on the water content of treated soil samples. The removal of PAH by Fenton-like treatment depended on the applied H2O2/soil weight ratio and ferrous ions addition. It was determined that the application of chemical oxidation in sand resulted in a higher PAH removal and required lower oxidant (ozone, hydrogen peroxide) doses. The enhancement of PAH biodegradability by different pre-treatment technologies also depended on the soil matrix. It was ascertained that combined chemical and biological treatment was more efficient in PAH elimination in creosote contaminated soil than either one alone. Thus, the combination of Fenton-like and the subsequent biological treatment resulted in the highest removal of PAH in creosote contaminated sand, and biodegradation with pre-ozonation was found to be the most effective technology for PAH elimination in peat.     

SPARROW Modeling of Nitrogen Sources and Transport in Rivers and Streams of California and Adjacent States,U.S.

The SPARROW (SPAtially Referenced Regressions On Watershed attributes) model was used to evaluate the spatial distribution of total nitrogen (TN) sources, loads, watershed yields, and factors affecting transport and decay in the stream network of California and portions of adjacent states for the year 2002. The two major TN sources to local catchments on a mass basis were fertilizers and manure (51.7%) and wastewater discharge (15.9%). Other sources contributed < 12%. Fertilizer use is widespread in the Central Valley region of California, and also important in several other regions because of the diversity of California agriculture. Precipitation, sand content of surficial soils, wetlands, and tile drains were important for TN movement to stream reaches. Median streamflow in the study area is about 0.04 m³/s. Aquatic losses of nitrogen were found to be most important in intermittent and small to medium sized streams (0.2‐14 m³/s), while larger streams showed less loss, and therefore are important for TN transport. Nitrogen loss in reservoirs was found to be insignificant, possibly because most of the larger ones are located upstream of nitrogen sources. The model was used to show loadings, sources, and tributary inputs to several major rivers. The information provided by the SPARROW model is useful for determining both the major sources contributing nitrogen to streams and the specific tributaries that transport the load.     

关于制定连云港市水土保持生态建设规划的思考

连云港市地处欧亚大陆桥的东桥头堡,是沿海十四个开放城市之一,国家定位是将其建设成为连接太平洋沿岸与中亚地区的国际商贸中心和全国性的旅游城市。而目前的山丘区水土流失严重,植被稀少,生态环境恶化,与国家定位目标和连云港市发展目标相差甚远。因此在制定水土保持生态环境建设规划时,必须紧紧围绕改善生态环境这条主线,以增加农民收入和改善生存条件为突破口,因地制宜,坚持长期综合治理,方能实现“山川秀美”之目标。     

Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South‐Central United States1

Rebich, Richard A., Natalie A. Houston, Scott V. Mize, Daniel K. Pearson, Patricia B. Ging, and C. Evan Hornig, 2011. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico From Streams in the South‐Central United States. Journal of the American Water Resources Association (JAWRA) 47(5):1061‐1086. DOI: 10.1111/j.1752‐1688.2011.00583.x Abstract: SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South‐Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas‐White‐Red, and Texas‐Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two‐thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%).