Detection of biotic responses to urbanization using fish assemblages from small streams of western Georgia,USA

We examined relationships between stream fish assemblages and land use alteration associated with urbanization in 15 lower Piedmont watersheds along an urbanization gradient north of Columbus, western Georgia. Based on land cover data from 2002 Landsat 7 TM imagery aerial photos, streams drained watersheds that were largely urban, developing (suburban), agricultural (pasture), managed pine forest, and unmanaged mixed-forest. We quantified fish seasonally from 3 run-pool segments in each stream, and used a variety of metrics as response variables in analyses of relationships between fish assemblage structure and land use and natural basin variation. In general, Georgia-Index of Biotic Integrity (GA-IBI) values, Bray-Curtis faunal similarity of streams to mean conditions within reference streams, proportions of fish as lithophilic spawners, and fish lacking eroded fins, lesions, tumors decreased with increasing urbanization. Multiple regression indicated that assemblages were explained by a combination of land use and natural basin variables (basin size, average discharge, nearest distance to a larger downstream tributary [colonization source]), with land use variables being important predictors of summer assemblages and natural basin variables being more important in winter and spring assemblages. Non-metric multidimensional scaling (NMDS) ordinations revealed strong separation between assemblages in urban watersheds and forested watersheds, whereas assemblages in agricultural and developing watersheds were intermediate between those in urban and forested watersheds. Our data suggest that fish are reliable indicators of anthropogenic disturbance at the landscape scale, at least seasonally, and may be used to forecast the magnitude of landscape-level changes in stream structure and function associated with the conversion of forests to urban/suburban land in the Southeast.     

Comparison of decapod communities across an urban-forest land use gradient in Puerto Rican streams

Urbanization influences a range of factors related to stream health, including the hydrologic regime, water quality, and riparian conditions that lead to negative effects on terrestrial and aquatic ecosystems. However, impacts on freshwater decapods from urbanization of tropical streams have not been reported. We hypothesized that changes in decapod communities in watersheds with different levels of urbanization are related to changes in physical stream habitats caused by different land uses and their effects on water discharge. The impacts of land use on the physico-chemical characteristics of streams and freshwater decapod communities were evaluated in three watersheds characterized by low, moderate and high-intensities of urbanization in Puerto Rico. For the low and moderately developed urban watersheds, decapod species richness ranged from 10 to 11 species; the highly urbanized watershed only had 4 species. Macrobrachium faustinum and Xiphocaris elongata were the most ubiquitously species and were found in all watersheds. Multivariable analysis of physical characteristics and densities of the decapod families resulted in one axis that explained 80 % of the total variation among the watersheds and was correlated with stream discharge. The effect of discharge is likely a result of frequent high flows that sustain habitats with high concentrations of dissolved oxygen and low concentrations of pollutants. An increase in physico-chemical parameters were observed from the LUW to the HUW. These results indicate that the decapod communities were most likely influenced by land use and environmental conditions that affected erosional aspects related to water discharge and water quality in the highly impacted watersheds.     

Direct and indirect effects of human population density and land use on physical features and invertebrates of Iowa (U.S.A.) streams

To improve understanding of human impacts on headwater stream condition, we quantified relationships between human, terrestrial landscape, and stream system variables in 29 central Iowa watersheds. Across study watersheds, between 0 and 100 % of total land area was characterized as “urban” (developed and barren land), whereas cultivated land constituted between 0 and 71 % of watershed area. Several variables were measured for each stream and associated watershed. Strengths of correlative relationships were used to select variables for path analysis, which we used to gain insight into factors affecting stream condition by evaluating direct and indirect effects of human system variables, terrestrial landscape variables, and physical stream variables on stream invertebrates. Results indicated that in predominantly urban watersheds, contaminant inputs to streams (measured by streamwater conductivity) negatively affected invertebrates, including EPT taxa (Ephemeroptera, Plecoptera, Trichoptera), and streamwater contaminant concentrations increased with impervious surface and human population density in the watershed. In rural watersheds, high streamwater nitrogen concentrations associated with cultivated land were related to declines in invertebrate taxon richness. Independent of land use, invertebrate abundance and taxonomic diversity were positively related to coarse substrate abundance on the streambed. Additionally, stream flow (discharge) increased with watershed area, which in turn increased invertebrate taxonomic diversity. Apparently, mechanisms responsible for human impacts on stream condition in central Iowa depend on dominant land use in the watershed. Additionally, stream ecosystems with high quality benthic habitat, and those located in large watersheds with greater flow, appear to be more resilient to land use effects.     

Connecting local environmental knowledge and land use practices: A human ecosystem approach to urbanization in West Georgia

Issues of urban sprawl and migration of exurban residents into the surrounding countryside of metropolitan areas have generated considerable debate across the US. These debates often revolve around the ecological footprint of urban areas and the erosion of quality of life indicators associated with rapid expansion of urban and residential areas. Although there has been much research done on the environmental and socioeconomic impacts of urbanization, little attention has been given to cultural impacts. This paper focuses specifically on the role of local environmental knowledge as an important resource in human ecosystems, and looks at the implications of environmental knowledge loss associated with urbanization and its related demographic changes. We compared environmental knowledge among rural, urban, and developing watersheds in western Georgia, and also look at relationships between local environmental knowledge and variables such as gender, education, income, and participation in outdoor recreational activities. We then explored how variations in environmental knowledge affected land use practices at the household level. The mean knowledge scores of residents in all three classifications of rural watersheds were higher than those living in developing and urban watersheds. We found residents of managed pine watersheds possessed the highest mean scores (p = 0.006), while urban watershed residents were the lowest. We also found that local environmental knowledge was influenced by active participation in outdoor recreation, with active bird-watchers having the highest environmental knowledge scores. However, we found less influence of factors such as education and income on environmental knowledge. We also found a clear connection between local environmental knowledge and land management practices. Timber owners scored higher than non-timber owners (p = 0.099), and landowners who constructed streamside management zones (SMZs) scored higher than those who did not (p = 0.034).     

Effect of urbanization on surface water chemistry in south-central Texas

The use of state factors can adequately describe the biogeochemistry and geochemistry of relatively undisturbed surface waters. Watersheds with increasing proportions of urban and suburban land use, particularly in sub-tropical, semi-arid and arid urban areas, that utilize irrigation for turfgrass and landscaping may have a low flow urban signature that relates to the source water used by municipal water suppliers. We examined thirteen watersheds; four with waste water treatment plants (24–67% urbanization), four rural (< 30% urbanization) and five urban (> 30% urbanization) in a humid sub-tropical oak savannah in south-central Texas. Three of our urban and one of our rural watersheds displayed the signature of municipal tap water. Three out of four watersheds with waste water treatment plants displayed the signature of treated sewage effluent. We suggest as a result of this study that the chemistry of municipal tap water particularly that with high sodium and bicarbonate, used in urban watersheds for irrigating turfgrass and landscapes may have detrimental effects on base flow stream water quality after it has interacted with watershed soils.     

The influence of exurban landscapes and local site characteristics on riparian vegetation

The southern Appalachian Mountains have experienced large population growth and a change in land use in the past 30 years. The majority of development has been low density, suburban land, known as exurban development. The long-term effects of exurbanization on riparian vegetative communities in the southeastern Appalachian Mountains are not well known. We sought to determine if vegetative community composition and structure change as a function of watershed–level variables such as time since neighborhood development or percent impervious surface within the watershed. We also assessed local–scale measures of disturbance such as canopy cover and basal area. Over two years we sampled a total of 27 streams in exurban watersheds ranging in age from four to forty-four years, along with eight forested streams. Watershed–scale variables such as neighborhood age and impervious surface cover did not influence the aspects of riparian vegetation community we measured. Canopy cover, a measure of local habitat disturbance, offered better predictions of vegetation community metrics. Exurban neighborhoods and their landowners may have the potential to manage for riparian vegetation through the use of maintained stream buffer zones along the entire length of the stream.     

Stream salamander responses to varying degrees of urbanization within Maryland’s piedmont physiographic province

The main objective of this study was to determine how stream salamander assemblages and species respond to varying levels of impervious surface cover within Maryland’s Piedmont physiographic province. We sampled stream salamanders in 21 first-order streams located in watersheds representing a range of impervious surface cover (0–24 %) across the northeastern part of Maryland’s Piedmont region. Habitat data, including stream substrate and riparian characteristics, were measured at each site. Eurycea bislineata was the predominant species of stream salamander encountered during this study (> 99 % of individuals) and most of these individuals were larvae (> 92 %). Consequently, statistical analysis was limited to E. bislineata larvae. We were unable to detect a difference in E. bislineata abundances or body mass index’s among varying levels of impervious surface cover % or any individual site habitat variables alone. These results suggest that in smaller watersheds within the Piedmont of Maryland, local habitat variables, in conjunction with land use variables, are necessary in determining the abundance and body mass index of E. bislineata larvae populations. This study makes a strong case for halting the over-simplification of the relationship between urbanization and the presence/abundance of stream salamanders.

     

Indigenous land rights and dynamics of the land market in Kuala Lumpur, Malaysia

This paper raises a number of important issues relating to legal and economic development concepts. It concentrates on the supply constraints affecting land development decisions of both private and public landowners in releasing land for development purposes. With reference to the indigenous land rights in Kuala Lumpur, this paper focuses on the restrictions in interest, which may limit the land from being transferred in the open market. With a limited market, the indigenous land achieves a lower value in the market place because transactions are limited within a particular group of people only. As a result, the market forces are restricted and the land development process for urban regeneration often comes to a halt. In examining the role of the indigenous land market in the redevelopment process of Kuala Lumpur, the study uses an institutional analysis to show the way in which these restrictions in interest affect landowners’ decisions and, thus, restrict the supply of land to real estate redevelopment. In conclusion, the paper shows various causes for land supply constraints and ways to improve these with the aim to undertake urban redevelopment initiatives considering pressure for more land in the market.     

Environmental and social predictors of phosphorus in urban streams on the Island of Montréal,Québec

Researchers have identified the importance of social characteristics for understanding ecological patterns in cities but the use of these characteristics in urban stream research has yet to be fully explored. Urban development is currently the second-largest cause of stream impairment in North America due in part to nutrient loading. However, research into factors that influence nutrient concentrations in urban streams is lacking. We sampled seven streams on the island of Montréal daily to measure phosphorus (P) concentration and P flux in each stream. We then compared stream P concentration and flux to several watershed characteristics commonly used to predict stream nutrients (e.g., watershed imperviousness, land use, existence of a riparian buffer) as well as several socio-economic characteristics of the watersheds (e.g., average home value, median household income). Overall, impervious surface cover and measures of land use were most effective at explaining the variation in P concentration and P flux in streams on the island of Montréal, while the riparian buffer and socio-economic variables were less effective. However, dollars spent on fertilizer per hectare of residential land and percent residential land use became important predictors of stream P concentration when impervious surface cover was removed from the regression model. This suggests that after accounting for the impact of physical watershed characteristics, social factors may be important predictors of urban stream P concentration. The results of our study suggest that more research is needed to determine the role that socio-economic variables play with respect to urban stream P.     

Urban growth boundary policy and residential suburbanization: Riyadh, Saudi Arabia

The process of suburbanization of Riyadh, a city of 4.5 million inhabitants, offers a unique situation in which the urban morphology of the city can be examined in light of socio-political and economic conditions. Central government ordinances helped create ‘dysfunctional’ sprawl by mandating big lots and overly wide streets. Fifty percent of the city’s urban plan of approximately 1300 km² represents a pattern of untimely, undeveloped subdivisions. Much of this premature sub-divisioning was a result of speculative land deals. The current area of undeveloped subdivided land is approximately 650 km², which is roughly the equivalent to the city’s land currently developed.The author argues that government policies and inefficient urban planning practices have encouraged the transformation of the peripheral desert landscape into unchecked land sub-divisioning championed by land developers and speculators. Using a comparative approach, the paper attempts to highlight sociopolitical and other cultural factors that underlie this inefficient sprawl at the fringe. It closes with recommendations to alleviate such a costly pattern that can be generalized to other developing world cities.     

Towards a theory of the American rural residential land market

Since the late 1960s there has been a notable acceleration in America in the demand for rural residential land within commuting range of urban and suburban employment and service opportunities. American rural residential households do not seem to purchase acreage tracts primarily for their ‘productive’, or resource value, however. Instead, they purchase rural land for its ‘consumptive’ or residential value, as its value is primarily derived from the bundle of residential attributes associated with it. Over time, rural land within commuting range of metropolitan areas becomes underproductive and idled — a situation which precedes urban sprawl. Rural residential development has thus become a focus of debate on the effects and inefficiencies associated with urban sprawl. Yet, not enough is known about the nature of the rural residential land market. It is argued that American rural residential households are different from their suburban and urban counterparts for at least three reasons. First, they are distinguishable for their pursuit of self-sufficiency, self-expression, and the cultural status that a rural residential lifestyle offers. Second, they seek low cost rural jurisdictions in order to afford more housing and land than they could afford in higher cost urban and suburban locations. Third, they value distance from the city center colinearly with externalities such as pollution, crime, overcrowding, and noise associated with central city areas. In the latter sense, American rural residential households value land more highly the farther away it is from the city center, but discount land value the farther away it is from the boundary of urban development. In light of these considerations, this paper (a) reviews the literature describing the motivations of American rural residential households, (b) poses a theory of the American rural residential land market, (c) applies the theory to a case study, and (d) offers implications of the theory to planning efforts aimed at preserving resource land and containing urban sprawl.     

Southern two-lined salamanders in urbanizing watersheds

Forested riparian buffers are an increasingly common method of mitigating the negative effects of impervious surface cover on water quality and wildlife habitat. We sampled larval southern two-lined salamanders (Eurycea cirrigera) in 43 streams, representing the range of impervious surface cover and forested riparian buffer width across Wake County, NC, USA. Larval abundance decreased with increasing impervious surface cover in the upstream catchment, but was not affected by buffer width. This is likely a result of an incomplete buffer system and culverts or other breaches along streams. Larval abundance increased with detritus cover in the stream to a threshold and then decreased as detritus continued to increase. As percent pebble substrate in the stream increased, especially in perennial streams, larval salamander abundance also increased. We suspect salamanders were unable to migrate with the water column during dry periods in intermittent streams with sedimented interstices below the surface, resulting in low abundances. A combination of increased peak flows and sedimentation, reduced base flow, and chemical changes likely reduces the abundance of salamanders in urban and suburban streams. We suggest creation of catchment-wide, unbreached buffers to maintain the integrity of stream habitats in urbanizing watersheds.     

Understanding the use of rural space: the need for multi-methods

Although the late 1990s saw increasing use of qualitative data in rural studies and a turn towards issues such as identities and the construction of rurality, many rural researchers still rely on a range of different methods and use both qualitative and quantitative data. However, the challenge of combining quantitative and qualitative data and using different methods is a theme not often dealt with in rural studies, at least not explicitly. This paper (re-)turns the attention to implications of using various methods and combining different types of data for studying a subject matter called ‘the use of rural space’. It concerns both physical land use and the practice and values of individual actors influencing the land use. We emphasise interplay between methodology and philosophy throughout the research process and argue for using multi-methods without compromising the integrity of the different methods. The methodological approach is a combined study of practice and values of individual actors. Two examples—one concerning Senegalese pastoralists’ livelihoods and their use of mobility and one concerning landowners’ location of field afforestation in Denmark—illustrate how the approach facilitates quite different studies of both practice and values and how quantitative and qualitative data can be combined in a non-eclectic way.     

Cairo's Zabaleen garbage recyclers: Multi-nationals’ takeover and state relocation plans

The paper investigates recently launched plans to privatize solid-waste management in Cairo, focusing on its adverse effects on the sustainability of the associated recycling economy and urban settlement system of the garbage collectors communities (Zabaleen) located within the Muqattam mountain area which is adjacent to Cairo's old historical quarters. According to official development strategy, the privatization of solid-waste services is regarded as fundamental to overall government plans for Old Cairo's rehabilitation. The objectives of the rehabilitation programme tend to favour tourist-orientated projects, whilst ignoring the local population's interests through the removal of informal Zabaleen settlements in Muqattam mountain, and through the clearing of the Eastern Cemetery of its tomb dwellers and shanty town buildings.The study examines the consequences of recent official intervention in the sustainability of the Muqattam Zabaleen settlement in terms of physical and demographic growth, infrastructural development, and changes in land tenure system. The paper takes into consideration early 1980s programmes funded by the World Bank to improve the Zabaleens’ environment and to upgrade their settlement. These aimed to maintain the existing informal settlement pattern and to develop urban service delivery systems.The empirical study adopts a qualitative analysis employing ethnographic techniques of informal discussions with secondary stakeholder agencies (local municipality, planners, NGOs activists). A field survey of the primary stakeholder group (garbage collectors) involved in-depth interviews with householders and with community leaders in the Zabaleen settlement. The analysis explores narratives expressed by members of the Zabaleen community in response to the threat of enforced eviction resulting from potential state-controlled gentrification programmes for urban development and land speculation in the area.The findings emphasize the significance of local participatory mechanisms in restructuring solid-waste collection and in developing the recycling industry whilst putting vacant and under-used areas into productive use. These mechanisms would support the management of built environment and local resources and would build local capacity through developing new channels for co-operation and partnership between the garbage collectors’ association (Gamm’yya) and grass roots organizations together with the local authorities and multi-national companies. In order to promote sustainable livelihoods and better opportunities for the urban poor the study concludes that there is a need to draw on the sustainable flow of local resources within low-income garbage collectors groups, whilst seeking new means of supporting land acquisition and its development for improved housing standards, basic services and environmental quality.     

Between argument and coercion: Social coordination in rural environmental governance

Increasingly, partnerships and other cooperative forms of governance are common-place in addressing problems of environmental management in rural landscapes. These forms of governance are multi-dimensional in the policy instruments employed; the make-up of actors; and, the types of rationalities that actors use to debate the problem and proposed solutions. This paper pursues the question of how different modes of social action, represented in argumentative claims of participants, influence social coordination in these governance arenas. An empirical study is presented of agri-environmental governance in Australia where actors debate planning and policy initiatives to reduce diffuse water quality impacts from farms on the adjacent Great Barrier Reef. Forester’s conceptualisation of practical social action which locates communicative action in the ‘real world’ of interest-based planning contexts, is used as an analytical frame to identify: (i) the type of claims made by governments, farmer groups and other actors in argumentation; (ii) the claims association with communicative, strategic and instrumental modes of action; and, (iii) their consequence for social coordination in formation and maintenance of inclusive, legitimate and viable forms of governing. The study finds that the interconnected character of claims made by actors, and the ready switching between modes of action observed, point to a situated and dynamic expression of rationality within these contested and prolonged debates on how to legitimately and effectively govern rural environments.     

Feeding,growth, and trophic position of redbreast sunfish (Lepomis auritus) in watersheds of differing land cover in the lower Piedmont,USA

One pervasive outcome in the urbanization of an ecosystem is the proliferation and numerical dominance of select tolerant organisms that are often native to the system yet with reduced relative abundances in less-disturbed conditions. As a result of high variation in environmental conditions between urbanized and non-urbanized systems, it is possible that the functional role of a ubiquitous organism is context dependent. Such is the case for redbreast sunfish (Lepomis auritus) in small streams in many parts of the Piedmont of the southeastern USA. To investigate this hypothesis, we evaluated the feeding, growth, and trophic position of redbreast sunfish in 3 streams of increasing levels of watershed urbanization (forested, suburban, urban) in the Lower Piedmont of western Georgia, USA. Through gut contents analysis, we found that sunfish consumed primarily Chironomidae (Diptera) larvae across all streams. However, fish in the suburban stream consumed more terrestrial prey than fish in the forest and urban streams, which corresponded to lower aquatic prey abundances in the suburban stream. Although there was no difference in mean fish age among streams, otolith analysis revealed that fish in the urban stream were larger at age than those in the forest stream. Last, stable isotope analysis revealed that fish in the urban stream occupied a lower trophic position than the other 2 streams. These results suggest that despite the fact that the primary prey resource was similar for sunfish in each stream, their potential functional role, as evidenced by size at age and trophic position, is context dependent.

     

Gender and housing : The provision of accommodation for young adults in three Mexican cities

The literature on gender and housing is oddly distorted, for it is dominated by research on households which are ‘women-headed’, even where the majority of women may live in households conventionally regarded as being headed by men. This literature shuns the ‘traditional’, male-headed, nuclear household and regards ‘non-traditional’ households as being those headed by single mothers or women living alone. The first part of this paper argues that it is important not to restrict discussion of gender and housing to the problems facing single mothers or women living alone, because there is a danger of rendering the majority of women, once again, invisible.Equating ‘traditional’ and ‘non-traditional’ households with ‘nuclear’ and ‘women-headed’ households, respectively, confuses structure with headship and overlooks cultural variations in what constitutes a ‘traditional’ household — the nuclear household is not necessarily the traditional norm. The second part of this paper explores a little-documented housing arrangement in which large numbers of women are involved in urban Mexico: sharing. ‘Sharing’ occurs when two or more households occupy the same plot of land; one household owns the plot, allowing the other(s) to live there rent-free. Sharing mostly involves the adult sons or daughters of the plot owners, and may be regarded as a variation on the extended household structure. Sons are more likely to be allowed to bring their wives to their parents' home, whereas daughters are more likely to leave. Women living with their in-laws lack security of tenure and there is often conflict between wives and members of their husband's family of origin, particularly their mothers-in-law.The anthropological literature has identified gender relations as the source of conflict between women in extended households. Sharing reduces the potential for conflict by giving the younger household greater autonomy. Furthermore, concern for their daughters' welfare leads many parents to offer accommodation to married daughters as well as sons. Single mothers, however, are more likely to live as part of their parents' household than to share. In this respect, the nuclear household norm is reinforced, since sharing seems to be a privilege accorded only to those who are married.     

Application of the experimental watershed approach to advance urban watershed precipitation/discharge understanding

Reliable methods are required to provide the detailed hydrologic information necessary to improve management of water resources and aquatic ecosystems in developing/urbanizing watersheds. A case study was implemented in a representative 230 km² mixed-use, urbanizing watershed to advance precipitation/discharge understanding. Precipitation and streamflow were monitored in five sub-watersheds (nested-scale experimental watershed study design), partitioned by dominant land use type. Data were collected at 30-min intervals through the 2009 to 2015 water years. Individual sub-watershed area-normalized flow and runoff coefficients differed by as much as 400%. Two high density, urban sub-watersheds displayed large runoff coefficients indicating disproportionately high flow response to precipitation inputs. Regression analyses of sub-watershed land use characteristics and flow metrics showed strong (i.e. R² > 0.9) statistically significant (p < 0.05) linear relationships for percentage developed, forest, and agriculture land cover. Observed relationships between land use and flow metrics illustrate the complexity of contrasting and intermingled land use types in urbanizing, mixed-land-use watersheds. Results highlight the variable hydrologic impacts of land use and suggest the potential for vegetation management as a tool for streamflow mediation in urban settings. The work is one of the first to utilize the experimental watershed method to isolate and quantify land use impacts in the context of a contemporary mixed-land-use watershed. Collectively, results emphasize the utility of the method for land and water resource managers seeking science-based information to guide management decisions and more effectively target remediation efforts in contemporary multiple-land-use watersheds.     

The urban watershed continuum: evolving spatial and temporal dimensions

Urban ecosystems are constantly evolving, and they are expected to change in both space and time with active management or degradation. An urban watershed continuum framework recognizes a continuum of engineered and natural hydrologic flowpaths that expands hydrologic networks in ways that are seldom considered. It recognizes that the nature of hydrologic connectivity influences downstream fluxes and transformations of carbon, contaminants, energy, and nutrients across 4 space and time dimensions. Specifically, it proposes that (1) first order streams are largely replaced by urban infrastructure (e.g. storm drains, ditches, gutters, pipes) longitudinally and laterally within watersheds, (2) there is extensive longitudinal and lateral modification of organic carbon and nutrient retention in engineered headwaters (3) there are longitudinal downstream pulses in material and energy exports that are amplified by interactive land-use and hydrologic variability, (4) there are vertical interactions between leaky pipes and ground water that influence stream solute transport, (5) the urban watershed continuum is a transformer and transporter of materials and energy based on hydrologic residence times, and (6) temporally, there is an evolution of biogeochemical cycles and ecosystem functions as land use and urban infrastructure change over time. We provide examples from the Baltimore Ecosystem Study Long-Term Ecological (LTER) site along 4 spatiotemporal dimensions. Long-term monitoring indicates that engineered headwaters increase downstream subsidies of nitrate, phosphate, sulfate, carbon, and metals compared with undeveloped headwaters. There are increased longitudinal transformations of carbon and nitrogen from suburban headwaters to more urbanized receiving waters. Hydrologic connectivity along the vertical dimension between ground water and leaky pipes from Baltimore??s aging infrastructure elevates stream solute concentrations. Across time, there has been increased headwater stream burial, evolving stormwater management, and long-term salinization of Baltimore??s drinking water supply. Overall, an urban watershed continuum framework proposes testable hypotheses of how transport/transformation of materials and energy vary along a continuum of engineered and natural hydrologic flowpaths in space and time. Given interest in transitioning from sanitary to sustainable cities, it is necessary to recognize the evolving relationship between infrastructure and ecosystem function along the urban watershed continuum.