Natural Drainage Research Articles

Ferric Uptake Regulator Provides a New Strategy for Acidophile Adaptation to Acidic Ecosystems.

Acidophiles play a dominant role in driving elemental cycling in natural acid mine drainage (AMD) habitats and exhibit important application value in bioleaching and bioremediation. Acidity is an inevitable environmental stress and a key factor that affects the survival of acidophiles in their acidified natural habitats; however, the regulatory strategies applied by acidophilic bacteria to withstand low pH are unclear. We identified the significance of the ferric uptake regulator (Fur) in acidophiles adapting to acidic environments and discovered that Fur is ubiquitous as well as highly conserved in acidophilic bacteria. Mutagenesis of the fur gene of Acidithiobacillus caldus, a prototypical acidophilic sulfur-oxidizing bacterium found in AMD, revealed that Fur is required for the acid resistance of this acidophilic bacterium. Phenotypic characterization, transcriptome sequencing (RNA-seq), mutagenesis, and biochemical assays indicated that the Acidithiobacillus caldus ferric uptake regulator (AcFur) is involved in extreme acid resistance by regulating the expression of several key genes of certain cellular activities, such as iron transport, biofilm formation, sulfur metabolism, chemotaxis, and flagellar biosynthesis. Finally, a Fur-dependent acid resistance regulatory strategy in A. caldus was proposed to illustrate the ecological behavior of acidophilic bacteria under low pH. This study provides new insights into the adaptation strategies of acidophiles to AMD ecosystems and will promote the design and development of engineered biological systems for the environmental adaptation of acidophiles.IMPORTANCE This study advances our understanding of the acid tolerance mechanism of A. caldus, identifies the key fur gene responsible for acid resistance, and elucidates the correlation between fur and acid resistance, thus contributing to an understanding of the ecological behavior of acidophilic bacteria. These findings provide new insights into the acid resistance process in Acidithiobacillus species, thereby promoting the study of the environmental adaptation of acidophilic bacteria and the design of engineered biological systems.

Possible effects of potential lahars from Cotopaxi volcano on housing market prices

The recent awakening of the Cotopaxi volcano in Ecuador set the conditions to estimate and verify the possible effects of potential lahars on residential housing unit prices. About 300,000 people live in the Los Chillos valley, which is the northern natural drainage of Cotopaxi’s lahars; therefore, the effects on house values can be significant. We have used housing information from 2016 of 240 properties to settle a hedonic price model within and outside of the lahar’s area. The regression model has a significant R2 value of about 0.723. The variable that determined the effects of potential lahar on the hedonic model demonstrates that the value of a residence house unit will increase its price by 41.99 USD for each meter away from the lahar path. Our study suggests that environmental disamenities generated by natural hazards will have a negative effect on residential house unit prices and we infer that consumers would be willing to pay a higher price in order to avoid such potential disamenities.

Characterizing nitrogen attenuation by headwater slope wetlands across different land uses

Rapidly increasing population pressure and land conversion from forests to urban and agricultural uses have been important stressors on coastal wetlands. Headwater wetlands in the southeast U.S. are particularly vulnerable because of their small size- they are easily filled or impacted through ditching, piping or impoundments. Since headwater areas have a disproportionately high influence on watershed flow and nutrient flux, alterations to their functionality can have impacts to downstream and coastal waters. Although headwater wetlands are generally understood to support water quality, the magnitude and mechanisms for this function are often uncertain. We compared flow, NO2−-N + NO3−-N (NO2 + NO3) concentrations, and NO2 + NO3 loads at the inlet and outlet of four headwater slope wetlands across common land covers/uses (i.e., commercial-urban, residential-suburban, agriculture, and forested) in coastal Alabama, USA. Watershed sizes draining to wetlands ranged from 0.5–1.8 km2 and each wetland showed distinct and shared trends. Measured NO2 + NO3 concentrations were typically low (<0.4 mg L−1) in all wetlands except for the agricultural watershed. The wetland in the residential watershed experienced high NO2 + NO3 loading rates into the wetland (21.6 kg ha−1 yr−1) however this was because of unusually high discharge to the wetland relative to its watershed size (overall mean: 0.13 m3 sec−1). Annual NO2 + NO3 loading rates from the forested and commercial-urban lands were much lower (<1.0 kg ha−1 yr−1). Despite drainage alterations at all sites, wetlands still provided annual NO2 + NO3 load reductions ranging from 13.1–62.0% although the commercial-urban wetland achieved reductions primarily through hydrologic recharge. Evidence from this study and others along the northern Gulf of Mexico coast indicate that low-order stream discharge can be relatively high and in some cases may drive high nutrient loading rates. Even though the natural drainage to most headwater wetlands has changed, they still can provide reliable attenuation of nitrate and other nutrients particularly where efforts are made to maintain a more natural wetland hydroperiod.

Assessment of surface runoff conditioned by road works and urban settlements in large plain basins

The province of Buenos Aires located in Argentina contains numerous agricultural plain basins of world importance among which the Samborombón river basin stands out, where regular floods affect agricultural activities and urban expansion. This sector has large road works with approach embankments that obstruct the natural drainage, a poorly planned urban growth, and an increase in the rainfall regime in recent decades. The aim of this work is to carry out an analysis and assessment of the surface runoff conditioned by road works and urban settlements in large plain basins, taking the Samborombón river basin as a case study. Satellite images were used to define the floodplain and identify the main road works and urban settlements that develop within it. Subsequently, hydrological simulations were carried out to assess how these anthropic structures modify the surface runoff and the flooded areas. To validate the simulation results, the flooded areas obtained were compared with a similar flood event of a Landsat image. The results show that the road works embankments and urban settlements restrict the floodplain area of the river, generating an increase in the flooded area and delaying the water runoff. This problem, together with the rainfall increase, shows the need to generate a territorial management plan and adopt mitigation measures. The use of sacrificial embankments could be an economic alternative that would prevent the obstruction of water runoff, being able to use the basin as a pilot site for this innovative idea.

Urban flood susceptibility zonation mapping using evidential belief function, frequency ratio and fuzzy gamma operator models in GIS: a case study of Greater Mumbai, Maharashtra, India

Greater Mumbai is one of the major sufferers of urban flood in India. In the present study, flood susceptibility zonation (FSZ) mapping of Greater Mumbai were performed using Geographical Information Systems (GIS) based models, evidential belief function (EBF), frequency ratio (FR), fuzzy gamma operator (FGO). For FSZ mapping, 12 conditioning factors were considered which included elevation, slope, plan curvature, topographic wetness index, stream power index, built-up index, geology, soil type, land use land cover, modified Fournier index, proximity to natural drainage and proximity to sewers and storm water drainage. The flood inventory database was divided into training and test data. The factor maps were integrated using GIS. The FSZ map was validated using area under curve (AUC) method. The AUC values of prediction rate using test data for FR, FGO, and EBF models were 0.7400, 0.7231 and 0.7268 respectively. The accuracy assessment of all three models shows fair prediction accuracy.

Flooding of Piazza San Marco (Venice): Physical Model Tests to Evaluate the Overtopping Discharge

This paper aims at evaluating the wave overtopping discharge over the pavement of “Piazza S. Marco” (Venice) in order to select the best option to mitigate the risk of flooding of the Piazza and to protect the monuments and historic buildings, e.g., the “Basilica S. Marco”. In fact, the MO.S.E. (MOdulo Sperimentale Elettromeccanico) system is designed to keep the water level below a certain value, for the safety of the lagoon, but it does not guarantee the defence of the Piazza, where flooding is still possible, being its pavement locally much lower than the maximum expected water level. To completely defend the Piazza, specific additional works are planned to prevent the back-flow through the natural drainage system (now the primary pathway) or by filtration or by overtopping. This paper investigates on the overtopping mechanism, under conditions compatible with a fully operational MO.S.E. system, through 2-D experiments. The pavement of the Piazza is gently sloping towards the masonry quay which, in some parts is formed by 5 descending steps, and in some other parts, is just a vertical wall. Close to the “Marciana” Library, a critical part is present, with a slightly lower crest freeboard. In total, three cross-sections were examined in the 36 m long wave flume of the Padova University. The test programme includes 10 irregular wave attacks and three different water levels. The test results differ considerably from the results of the available formulas, since the investigated cross-sections by far exceed their range of applicability. The presence of the steps affects only the reflection coefficient rather than the overtopping discharges. In general, if the waves incident to the Piazza are higher than 40 cm, which is a possible scenario, some other adaptation works must be considered, such as the pavement rise, temporary barriers or the reduction of the waves impacting the quay through, for instance, floating breakwaters.

Challenges for the sustainable use of water and land resources under a changing climate and increasing salinization in the Jizzakh irrigation zone of Uzbekistan

Jizzakh Province in Uzbekistan is one of the largest irrigated areas in Central Asia without natural drainage. In combination with aridity, climate change and extensive irrigation practices, this has led to the widespread salinization of agricultural land. The aim of this study was to identify opportunities to improve the reclamation status of the irrigated area and how best to effectively use the water resources in Jizzakh Province based on investigations conducted between 1995 and 2016. A database of field measurements of groundwater levels, mineralization and soil salinity conducted by the provincial Hydro-Geological Reclamation Expeditions was used in the study. The total groundwater mineralization was determined using a portable electric conductometer (Progress 1T) and the chloride concentration was determined using the Mohr method. The soil salinity analyses were conducted by applying two different methods: (1) the extraction and assessment of the soluble salt content, and (2) using an SM-138 conductivity sensor applied to a 1:1 mixture of soil sample and water. The analyses of the monitoring results and the salt balance in the “irrigation water-soil-drainage water” system clearly demonstrated that the condition of the irrigated land in the province was not significantly improved. Under these conditions, the stability of crop yields is achieved mainly through the use of large volumes of fertilizer. However, excess amounts of mineral fertilizers can also cause the salinization of soils. The average groundwater salinization value in most of the irrigated land (75.3%) fluctuated between 1.1 and 5.0 g/L, while the values were less than 1.0 g/L in 13.1% of the land and in the range of 5.1–10.0 g/L in 10.5% of the land. During the period of 1995–2016 the salinization level of the irrigated land in Jizzakh Province increased slightly and the area could be divided into the following classes: no salinity (17.7% of the total area), low salinity (51.3%), moderate salinity (29.0%), and high salinity (2.0%). Detailed studies of the salt balance in irrigated land, the impact of climate change, increased fertilizer use, and repeated remediation leaching on the groundwater level and mineralization should be conducted in the future, due to the possibility of accelerated salinization, fertility decline, and reduced yields of agricultural crops.

INFLUENCE OF DRAINAGE METHODS ON SOYBEAN DEVELOPMENT IN LOWLANDS

ABSTRACT The need for crop rotation and profitability in lowland areas are the two main reasons for the introduction of soybean cultivation in the state of Rio Grande do Sul, Brazil. These areas have poor natural drainage, which impedes proper soybean growth. In this sense, this study aimed to assess the efficiency of using broad base ridges in comparison to the surface drainage for soybean cultivation in lowlands. The study was conducted during the 2014/2015 and 2015/2016 growing seasons in Sao Joao do Polesine, RS, Brazil. The assessed drainage methods were the use of broad base ridges with different width dimensions (22.5, 15.0, and 7.5 m) and surface drainage. The results showed that the shoot dry matter and leaf area index have similar behavior. The broad base ridge was better than the surface drainage method for these variables. The 7.5-m broad base ridge stood out among the treatments when compared to the others, as it had the best results for the leaf area index (8.66), plant height (102.5 cm), and shoot dry matter (33.06 g).

Efficiency and productivity of irrigation water based on water balance considering quality of return flows

Efficiency is one of the most important assessment indicators in irrigation systems. Classical efficiency (CE) is not an exact index due to the lack of consideration of the return flows. Therefore, the neoclassical concepts of the efficiency are considered to take a part of losses of irrigation water as a return flow into account. Quality of the return flows may change in their path and it must be considered in evaluating the efficiency and productivity of irrigation water. This research was carried out to investigate this challenge. Sustainable efficiency (SE) was applied based on the water balance and quality of return flows. The methodology and detail for computing different parameters and their quality and beneficial coefficients in water balance equation were presented. Moghan irrigation and drainage network in the northwest of Iran was selected as the study area and CE and SE were calculated in meso and micro levels using the meteorological data, cropping pattern, irrigation water volume, natural and artificial drainages, infiltration and return flow quality. In addition, the irrigation water productivity was calculated by considering the volume of water based on the different concepts of efficiency. Quality coefficient related to return flow had different values in different months (0.85 in August and 1 in November and December). The results showed that about 87 % of inflow, 91 % of the rainfall, 89 % of the evapotranspiration, 13 % of the non-reusable water, and 91 % of the return flow were useful in the study area. The highest and the lowest efficiencies are occurred in September and November, respectively. The average of meso and micro Sefficiencies were 72 % and 47.5 %, respectively, and the CE was 37.9 %. The results showed that water productivity based on the SE is more than that of the CE. The water productivity at the meso level also showed a higher value than at the micro level.

Life cycle cost savings analysis on traditional drainage systems from low impact development strategies

Areas that are covered with natural vegetation have been converted into asphalt, concrete, or roofed structures and have increased surface impermeability and decreased natural drainage capability. Conventional drainage systems were built to mimic natural drainage patterns to prevent the occurrence of waterlogging in developed sites. These drainage systems consist of two major components: 1) a stormwater conduit system, and 2) a runoff storage system. Runoff storage systems contain retention basins and drywells that are used to store and percolate runoff, whereas conduit systems are combination of catch basins and conduit pipes used to collect and transport runoff. The construction of these drainage systems is costly and may cause significant environmental disturbance. In this study, low impact development (LID) methods that consist of extensive green roofs (GRs) and permeable interlocking concrete pavements (PICPs) are applied in real-world construction projects. Construction project documents were reviewed, and related cost information was gathered through the accepted bidding proposals and interviews of specialty contractors in the metropolitan area of Phoenix, Arizona. Results indicate that the application of both LID methods to existing projects can save an average of 27.2% in life cycle costs (LCC) for a 50-year service life and 18.7% in LCC for a 25-year service life on the proposed drainage system, respectively.

Использование компьютерной навигационной системы при риносинусохирургии

According to world statistics, of ENT pathology (throat, ear and nose) is among the most common diseases. About 30% of the world’s population constantly suffers from ENT pathology, which leads to a deterioration in the quality of life and disability. One of the most common pathologies of the upper respiratory tract is diseases of the paranasal sinuses (PNS). To date, maximum functionality and minimal trauma to the surgical treatment of ENT diseases, can achieve a functional minimally invasive surgery (Functional Endosocopic Sinus Surgery, FESS), in which the restoration of the natural ventilation and drainage pathways occurs with minimal trauma to the mucous membrane and the anatomy of the structures of the nose and PNS with local surgeries under constant endoscopic control. Endoscopic sinus surgery is a widely used method of surgical treatment of diseases of the nose and paranasal sinuses.The article analyzes the various methods of endoscopic surgery of the paranasal sinuses, describes their positive and negative sides, including the use of a computer navigation system. Data search was carried out in the database PubMed, CRD, Cochrane etc. by keywords. The search for modern solutions of endoscopic sinus surgery determines the relevance of the navigation system in sinus surgery.

Determination of Hydrogeological Characteristics by Mikala 2 Well Pumping Test In The Commune of N’sele / Kinshasa R.D.Congo

This work is of particular interest in the field of rational and sustainable management of water wells since the study of the capacity of the aquifer makes it possible to know the quantity of water that can be taken from the tablecloth, so as not to lead to its exhaustion. The hydrogeological characteristics obtained also make it possible to understand the capacity of the aquifer to react to its drainage by wells or to natural drainage by rivers in its hydrogeological watershed or to its water supply. The objective of this work is to determine the best hydrogeological method, the hydrogeological characteristics of the aquifer that feeds the Mikala 2 well in the municipality of Nsele. These are the transmissivity, the hydraulic conductivity, the storage coefficient and the diffusivity coefficient of the water table in the municipality of Nsele.

Geo‐environmental evaluation for the preventive conservation of open‐air archaeological sites: the case of the Roman Necropolis of Carmona (Spain)

AbstractThe Necropolis of Carmona, which has more than 600 tombs carved in calcarenites, is among the most important Roman burial sites preserved in southern Spain. The tombs in the Necropolis show severe alteration and multiple weathering processes after being excavated at the end of the nineteenth century without a preventive conservation plan. The archaeological site shows strong anthropic modifications related to different excavation stages and in relation to the construction of facilities for the visiting public. In particular, the exposure of the buried tombs to meteoric conditions and anthropic modification of natural drainage have led to an important acceleration of the deterioration of the tombs. The conservation status of the Necropolis was defined through a comprehensive geo‐environmental study that combined field observations and laboratory data, modelling and digital mapping and environmental monitoring. Results allow a methodology to be developed providing guidelines to minimize potential risks when excavating new tombs (now buried) in the future. Moreover, the most suitable prospective areas can be defined inside the Necropolis in terms of the environmental, geological and geomorphological conditions which will enhance the preservation of newly exhumed tombs. Geo‐environmental preventive conservation methods that we propose can be entirely applied to other large archaeological sites completely exposed to open‐air atmospheric conditions.

Exploring the application of topographic indices in urban areas as indicators of pluvial flooding locations

AbstractIn urban areas, the presence of impervious surfaces limits natural drainage and routes water to stormwater infrastructure with finite capacity, making these areas especially prone to flooding. Though large floods are responsible for endangering lives and causing extensive damage, there is growing evidence that more frequent floods with shallow water depths, termed nuisance flooding, can have a high cumulative cost and many direct and indirect damages. To determine whether locations of nuisance flooding may be linked to topography, we took a parsimonious, spatially distributed approach to explore whether high topographic index values co‐occur with citizen‐reported nuisance flooding. We obtained nuisance flood reports from the municipal data service 311 for several watersheds in New York City and Baltimore, USA. Our analysis tested two topographic indices (TI)—topographic wetness index (TWI) and sink depth—both calculated from high‐resolution (~1 m) digital elevation models. Generally, our findings suggest that not all but many locations of reported flooding tend to coincide with deep sinks or large TWI. However, nuisance flooding reports most commonly coincided with deep sinks and high TWI when using a maximum, instead of coincident, TI value extracted around each reported location of flooding, an approach we used due to the uncertainty in location accuracy of flooding reports. Overall, our results show promise for application of topographic indices, typically applied in more natural settings, as indicators of nuisance flooding areas in urbanized environments. Although limitations to this approach exist, the application of TIs and crowd‐sourced reporting in tandem could provide a useful starting point for mapping flood‐prone areas in many cities with technologically adept community members and ample geospatial data.

Field trials to detect drainage pipe networks using thermal and RGB data from unmanned aircraft

The use of drainage pipe is documented as far back as 200 B. C. and continues to be used in poorly drained agricultural regions throughout the world. While good for crop production, the eco-hydrologic impacts of this modification have been shown to adversely affect natural drainage networks. Identifying the exact location of drainage pipe networks is essential to developing groundwater and surface water models. The geometry of drainage pipe networks installed decades ago has often been lost with time or was never well documented in the first place. Previous work has recognized that drainage pipes can be observed for certain soil types in visible spectrum (RGB) remote sensing data due to changes in soil albedo. In this work, small Unmanned Aerial Systems (sUAS) were used to collect high resolution RGB and thermal data to map subsurface drainage pipe. Within less than 96 h of a small (< 1.3 cm) rain event, a total of approximately 60 ha of sUAS thermal and RGB data were acquired at two different locations in the IML-CZO in Illinois. The thermal imagery showed limited evidence of thermal contrast related to the drainage pipe. If the data were acquired immediately after a rain event it is more likely a temperature contrast would have been detected due to lower soil moisture proximal to the drainage pipe network. The RGB data, however, elucidated the drainage pipe entirely at one site and elucidated traces of the drainage pipe at the other site. These results illustrate the importance of the timing of sUAS data collection with respect to the precipitation event. Ongoing related work focusing on laboratory and numerical experiments to better quantify feedbacks between albedo, soil moisture, and heat transfer will help predict the optimal timing of data collection for applications such as drainage pipe mapping.

Se(VI) sorption from aqueous solution using alginate/polyethylenimine membranes: Sorption performance and mechanism

New high percolating alginate membranes are designed without using sophisticated drying methods: negatively charged alginate reacts with positively charged polyethylenimine (PEI), prior to be crosslinked with glutaraldehyde and air-dried. This is sufficient to obtain a highly macroporous structured membrane. Highly percolating properties of these new A-PEI membranes make the material applicable in natural drainage systems. The high density of amine groups in composite membranes explain their high affinity for anions in acidic solutions. FTIR, SEM-EDX and XPS analysis are used to explore the sorption mechanism. Se(VI) is sorbed through electrostatic attraction between positive amine groups and negative selenium anions; in a second step, bound Se(VI) is reduced by amine and hydroxyl groups in acidic conditions. A-PEI membranes are successfully used for recovering Se(VI) anions at pH 2. The maximum sorption capacity is close to 83 mg Se g−1; the sorption isotherm is described by the Sips and Langmuir equations. The membranes are poorly sensitive to flow rate in the range 15–50 mL min−1. The kinetic profiles are fitted by the pseudo-first order rate equation. Solute desorption is operated using NaOH solutions; the sorbent shows a remarkable stability in sorption and desorption properties for a minimum of 4 cycles.

Active tectonics and drainage evolution in the Tunisian Atlas driven by interaction between crustal shortening and mantle dynamics

Active tectonics in North Africa are fundamentally driven by NW-SE directed slow convergence between the Nubia and Eurasia plates, leading to a region of thrust and strike-slip faulting. In this paper, we analyse the morphometric characteristics of the northern Tunisia sector. We aim to identify unknown active tectonic structures, and to further understand the mechanisms driving the drainage evolution in this region. The interpretation of morphometric data was ground-truthed with field data. Our analysis indicates that recent fluvial captures have been the main factor driving fluvial network reorganization in NE Tunisia. The Medjerda River has increased its drainage area during the Quaternary by capturing adjacent axial valleys to the north and south of its drainage divide. These captures are probably driven by the gradual uplift of adjacent axial valleys by reverse/oblique faults or associated folds like El Alia-Teboursouk and Dkhila faults. Our fieldwork found that these faults cut Holocene sediments thus showing recent fault activity. The growth and stabilization of the axial Medjerda River, contrary to the natural transverse drainage development of mature orogens, might be caused by a combination of crustal shortening structures and mantle dynamic processes. The Medjerda River flows SW-NE from the South Atlassic dextral transfer zone to the regional topographic low defined by the Gulf of Gabes and the Straits of Sicily, which in turn, may be influenced by the underlying Tunisian slab in the region.

Design of drainage system on industrial area Kampung Cina, Dobo City, Aru Islands Regency, based on Eco drainage using with HEC-RAS 4.0

This study aim to plan a drainage system in the Industrial area of Kampung Cina Dobo City that can overcome the problems of inundation occurred. The inundation is caused by the drainage channel that has not been properly arranged and is still in the form of a natural drainage channel, most of which still use the road drainage network whose condition is not functioning properly due to sediment and garbage which results in many drainage channels being cut off. Data processing is carried out with two analyzes including hydrological analysis and hydraulic analysis. The hydraulics analysis includes channel section planning and drainage system modeling with HEC-RAS 4.0 software. In conventional drainage discharge flowing in the channel before the end of drain amounted to 1,136 m3/sec. Once added a retention pond with a capacity of 10.358 m3 with 5 scenario dimensions spillway. The results of modeling obtained by the reduction of the maximum flood flow is 1,07 ms / sec with dimensions of aperture is 8 m x 0,8 m and lower the water level in the upstream channel by 31 cm and 44 cm in the downstream channel.

Delineation of Flood Risk Zones in Hyderabad City: GHMC-West Zone

Increase in urbanization leading to climate changes and human activities have resulted in flash flood scenarios with varying intensity rainfalls in the city. The uneven distribution of rain fall coupled with Mindless urbanization, encroaching upon and filling up of natural drainage channels and lakes to use the high-value urban land for buildings are the main causes of urban flooding. The built environment of urban areas transforms the natural pervious environment into impervious ground surfaces, inhibiting infiltration. Since water cannot infiltrate into the ground in these urban impervious surfaces, it runs across the surface when it rains and as the surfaces become larger and steeper the speed and quantity of runoff increases.

Total Recoverable Aluminum: Not Totally Relevant for Water Quality Standards.

A large water quality data set, representing more than 100 surface-water locations sampled from 2007 to 2017 in the Los Alamos area of New Mexico, USA's Pajarito Plateau, was assembled to evaluate Al concentrations in unfiltered and filtered samples. Aluminum concentrations often exceeded United States Environmental Protection Agency (USEPA) and New Mexico ambient water quality criteria (AWQC), regardless of filter size and sample location. However, AWQC are based on laboratory toxicity studies using soluble Al salts and do not reflect natural conditions in Pajarito Plateau surface waters. The plateau is predominately covered by glassy and recrystallized volcanic ashes (e.g., Bandelier Tuff) containing colloidal to sand-sized aluminosilicates. Samples from natural background drainages and areas downstream of developed regions exhibited similar Al concentrations, suggesting that AWQC exceedances are caused by naturally elevated Al concentrations. Solubility calculations indicated that most samples were oversaturated with respect to amorphous Al(OH)3 (s). Therefore, AWQC exceedances are likely artifacts of the "total recoverable" sample preparation, which includes acidification and partial digestion, thereby liberating nonbioavailable Al from aluminosilicates. Accordingly, Al concentrations were strongly associated with suspended sediment concentrations (SSCs), implying that aluminosilicates in suspended sediment contributed to AWQC exceedances and Al oversaturation. Solid-phase particle characterization, using X-ray diffraction (XRD) and scanning electron microscopy with electron dispersive spectroscopy (SEM/EDS) did not identify potentially bioavailable amorphous Al(OH)3 (s) in any sample tested. Thus, current sample collection and analysis protocols should not be used to evaluate attainment of Al AWQC on the Pajarito Plateau or locations where aluminosilicates are substantial contributors to total recoverable Al. A sample preparation method (e.g., pH 4 extraction) capable of differentiating nonbioavailable and bioavailable forms of Al is recommended. Otherwise, current New Mexico and USEPA sample preparation approaches will continue to generate artifactual AWQC exceedances in surface waters that contain aluminosilicates. Integr Environ Assess Manag 2019;00:1-14. © 2019 SETAC.