Density Residential Research Articles

Pollution characteristics and health risk assessment of heavy metals in street dusts from different functional areas in Beijing, China

Street dusts from Heavy Density Traffic Area, Residential Area, Educational Area and Tourism Area in Beijing, China, were collected to study the distribution, accumulation and health risk assessment of heavy metals. Cr, Cu, Zn, Cd and Pb concentrations were in higher concentrations in these four locations than in the local soil background. In comparison with the concentrations of selected metals in other cities, the concentrations of heavy metals in Beijing were generally at moderate or low levels. Ni, Cu, Zn and Pb concentrations in the Tourism Area were the highest among four different areas in Beijing. A pollution assessment by Geoaccumulation Index showed that the pollution level for the heavy metals is in the following order: Cd>Pb>Zn>Cu>Cr>Ni. The Cd levels can be considered “heavily contaminated” status. The health risk assessment model that was employed to calculate human exposure indicated that both non-carcinogenic and carcinogenic risks of selected metals in street dusts were generally in the low range, except for the carcinogenic risk from Cr for children.

Enhancing a rainfall-runoff model to assess the impacts of BMPs and LID practices on storm runoff

Best management practices (BMPs) and low impact development (LID) practices are increasingly being used as stormwater management techniques to reduce the impacts of urban development on hydrology and water quality. To assist planners and decision-makers at various stages of development projects (planning, implementation, and evaluation), user-friendly tools are needed to assess the effectiveness of BMPs and LID practices. This study describes a simple tool, the Long-Term Hydrologic Impact Assessment-LID (L-THIA-LID), which is enhanced with additional BMPs and LID practices, improved approaches to estimate hydrology and water quality, and representation of practices in series (meaning combined implementation). The tool was used to evaluate the performance of BMPs and LID practices individually and in series with 30 years of daily rainfall data in four types of idealized land use units and watersheds (low density residential, high density residential, industrial, and commercial). Simulation results were compared with the results of other published studies. The simulated results showed that reductions in runoff volume and pollutant loads after implementing BMPs and LID practices, both individually and in series, were comparable with the observed impacts of these practices. The L-THIA-LID 2.0 model is capable of assisting decision makers in evaluating environmental impacts of BMPs and LID practices, thereby improving the effectiveness of stormwater management decisions.

Nutrient Enrichment and Hypoxia Threat in Urban Surface Water

Water samples pooled from nine urban streams/rivers traversing high density residential and commercial areas in the Abeokuta metropolis, Ogun State, Nigeria, were investigated in order to determine the effect of inorganic nutrients on oxygen distribution between 2008 and 2010 by using standard methods. Results revealed that the metropolitan streams/rivers are anoxic and hypoxia‐threatened due to high nutrient load (NL) except in peri‐urban streams/river which served as control. The pH was 6.6–6.9 and the concentrations of dissolved organic carbon, total nitrogen and phosphorus (P‐PO43−) of the streams/rivers were 24.8–155.4, 3.82–15.46 and 1.35–5.71 mg/L, respectively, while dissolved oxygen (DO) ranged between 3.25 and 7.46 mg/L. The results also showed that the biochemical oxygen demand and chemical oxygen demand values ranged between 180.81 and 200.62, 250.27 and 312.83 mg/L, respectively. Analysis of variance showed significant differences between sampling sites as well as seasons (wet and dry) in terms of NL and oxygen levels in all the stream/river water samples investigated with those from residential locations having higher NL values during the dry season. Thus, DO levels in almost all the urban streams/rivers were low, hence the need for regulatory intervention to ensure point of compliance necessary to protect inland freshwater from sewage inlets.

사회-환경적 지속가능성을 고려한 홍콩의 고층고밀주거 계획기법 - 홍콩 공공주택 사례를 중심으로 -

The purpose of this study was to find design methods as regards high rise-high density residential for socio-environmental sustainability in high density society. To do this, this study focused on Hong Kong and its public high density housing as the highest dense housing types and society. Since 1960s, Hong Kong has provided high rise-high density public housing which could not help confronting various problems related to social and environmental problems and tried to solve them. Thus, it would be worthy that analysing and reviewing long-range design considerations of Hong Kong Government and Hong Kong Housing Authority. Design strategies and methods extracted from this study may go some way towards finding our own design solution in near future of high density.

Konsep Pengembangan Ruang Terbuka Hijau (RTH) pada Permukiman Kepadatan Tinggi

Salah satu langkah perwujudan konsep Eco Cultural City Kota Surakarta dilakukan dengan adanyaupaya untuk meningkatkan kualitas dan kuantitas Ruang Terbuka Hijau (RTH), khususnya padakawasan permukiman padat. Pengembangan RTH pada permukiman kepadatan tinggi menjadifenomena menarik untuk diteliti yang kemudian diangkat menjadi pertanyaan penelitian (researchquestion) yaitu: bagaimana konsep pengembangan RTH pada permukiman kepadatan tinggi?. Tujuanpenelitian ini adalah untuk menyusun konsep pengembangan RTH pada permukiman kepadatan tinggi.Adapun sasaran dalam penelitian ini antara lain mengkaji karakteristik permukiman kepadatan tinggi,mengkaji karakteristik RTH permukiman kepadatan tinggi, menganalisis tipologi RTH permukimankepadatan tinggi, dan menganalisis pengembangan RTH permukiman kepadatan tinggi dalam konsephuman settlement. Penelitian ini dilakukan dengan menggunakan pendekatan kuantitatif. Konseppengembangan RTH dalam konsep human settlement diarahkan dalam pencapaian elemen nature(alam) dan elemen society (masyarakat) pada masing-masing tipologi RTH yang terbentuk. Salah satubentuk konsep pengembangan RTH dilakukan dengan mengoptimalkan lahan melalui media tanamberupa pot-pot tanaman.Kata kunci: konsep pengembangan RTH, permukiman kepadatan tinggi

Assessing the stability of annual temperatures for different urban functional zones

The urban functional zone (UFZ) is the basic unit of urban planning, which is defined as an area of similar social and economic functions. Despite the importance of UFZs, the stability of their annual temperature between winter and summer has seldom been investigated. With an understanding of the thermal impacts that planning decisions can have, it is essential to know how UFZs can be designed to regulate temperatures in the urban environment. 690 UFZs were identified using ALOS images in 2009 in Beijing. Land surface temperature (LST) was extracted from daytime Landsat TM (2002) and ASTER (2009) images. The regional LST variation of 31 district-sized sub-regions was correlated to the types of UFZs in the region and structural features of the region such as area, size, diversity, complexity and connectivity. Results showed that: (1) UFZ types, in order from highest to lowest LST variation, were commercial, campus, high density residential, water, recreational, low density residential, road, preservation, and agricultural zones; (2) the regional LST variation was positively correlated with the area of campus, commercial, high density residential, water, and road zones, but negatively correlated with the area of agricultural and low density residential zones; (3) increased connectivity and complexity decreased regional LST variations. The results indicated that the stability of annual temperatures was determined not only by the UFZ type and size but also by the connectivity and complexity. These results are clearly useful and essential pieces of information that can be applied in urban planning to improve climate adaptability.

Land cover controls on summer discharge and runoff solution chemistry of semi-arid urban catchments

Summary Recharge of urban runoff to groundwater as a stormwater management practice has gained importance in semi-arid regions where water resources are scarce and urban centers are growing. Despite this trend, the importance of land cover in controlling semi-arid catchment runoff quantity and quality remains unclear. Here we address the question: How do land cover characteristics control the amount and quality of storm runoff in semi-arid urban catchments? We monitored summertime runoff quantity and quality from five catchments dominated by distinct urban land uses: low, medium, and high density residential, mixed use, and commercial. Increasing urban land cover increased runoff duration and the likelihood that a rainfall event would result in runoff, but did not increase the time to peak discharge of episodic runoff. The effect of urban land cover on hydrologic responses was tightly coupled to the magnitude of rainfall. At distinct rainfall thresholds, roads, percent impervious cover and the stormwater drainage network controlled runoff frequency, runoff depth and runoff ratios. Contrary to initial expectations, runoff quality did not vary in repose to impervious cover or land use. We identified four major mechanisms controlling runoff quality: (1) variable solute sourcing due to land use heterogeneity and above ground catchment connectivity; (2) the spatial extent of pervious and biogeochemically active areas; (3) the efficiency of overland flow and runoff mobilization; and (4) solute flushing and dilution. Our study highlights the importance of the stormwater drainage systems characteristics in controlling urban runoff quantity and quality; and suggests that enhanced wetting and in-stream processes may control solute sourcing and retention. Finally, we suggest that the characteristics of the stormwater drainage system should be integrated into stormwater management approaches.

Sustainable Development Planning: A Case of Public Participation using Online Forums

Public participation in Sustainable Development Planning (SDP) of cities represents significant challenges to governments and private organizations responsible for developing infrastructure. In this study, a regional government used a series of electronic discussion papers and questions to enable online forum discussions and exchanges between 196 participants on the major SDP issues related to city development up to 2030. This study used a rigorous and structured QSR nvivo analysis of 690 online forum postings to determine the participants' major SDP concerns for the city over a 20-year period. The collective results of the investigation show that future integrated transport networks, higher density residential and commercial land use, and sustainable population growth are still the subject of concern and intense debate among forum participants, SDP experts and the government. The research also demonstrates the capacity of green information and technology systems to serve as important mechanisms for SDP participation and consultation. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment

Assessment of spectral, polarimetric, temporal, and spatial dimensions for urban and peri-urban land cover classification using Landsat and SAR data

Urban and peri-urban environments are composed of a wide variety of materials, making land cover classification challenging. The objective of this research is to determine how effectively multi-season Landsat Enhanced Thematic Mapper Plus (ETM+) and single-season Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data can be combined to map 17 land cover categories in the Greater Boston area of, Massachusetts, USA. The key goal of this work is to test the integration of radar and optical data. The contribution of different dimensions of input data to a random forest classifier was evaluated with map accuracy statistics. PALSAR data produced a 30.99% overall classification accuracy. Higher classification accuracy (72.24%) was achieved by adding texture variables derived from the PALSAR data. A September Landsat image produced a map accuracy of 77.96%. The inclusion of Landsat images from other three seasons increased map accuracy to 86.86% and Landsat derived texture variables further increased the map accuracy to 92.69%. The highest map accuracy (93.82%) was achieved by combining Landsat and PALSAR. Though combining PALSAR and Landsat only increased the overall accuracy by 1.1%, it was a statistically significant increase, whose magnitude was limited by the high accuracy already achieved with Landsat data. Moreover, confusion matrices and land cover maps indicated that most of this increase was from three urban land cover types ( low density residential, high density residential, and commercial/industrial). The results demonstrate the value of combining multitemporal Landsat imagery, ALOS PALSAR data, and texture variables for land cover classification in urban and peri-urban environments.

European NO2 land use regression incorporating satellite- and ground-based measurements

Background and Aims: Land use regression (LUR) models have increasingly been applied to assess air pollution exposures typically at the city level. Fewer examples at the continental scale exist. With recent improvements in data quality and availability, including pollutant measurements from satellites such as Ozone Monitoring Instrument (OMI), modelling over larger areas at finer spatial resolutions is possible. Methods: Land use regression was used to model ambient NO2 using ca. 2000 monitoring sites across Western Europe from the Airbase network. The network includes sites located in background, industrial and traffic environments. Characteristics of land use in buffers from 100 to 10,000m included high and low density residential, industrial, ports, urban green space, total built up, and natural areas. Major, secondary and local roads, derived from a 1:5,000 road network for Europe, were extracted in buffers up to 1000m. Information on altitude, population density and distance to sea were also available. LUR models with and without satellite-derived (OMI) NO2 concentrations were explored for years 2005-2007 for all sites combined. Results: Preliminary results for year 2007 indicate a model performance of R2 = 0.49, with a SEE of 0.452 based on annual-mean concentrations (natural log) at monitoring sites. Inclusion of satellite data improves model performance (R2: 0.44 without satellite data, 0.49 with satellite data). Current refinements to the model are expected to improve performance. Preliminary models include satellite measurements, proportion of built up land, local roads and major roads as the most important independent variables. LUR models for 2005 and 2006 will also be presented. Conclusions: Preliminary results support the potential to build a Europe-wide LUR models for NO2 using readily available data. Satellite-derived measures of ground-level NO2 appear to improve model performance. Our results will be used to construct high resolution (~100m) maps of NO2 concentrations across Western Europe.

Building Extraction from High Resolution Space Images in High Density Residential Areas in the Great Cairo Region

This study evaluates a methodology for using IKONOS stereo imagery to determine the height and position of buildings in dense residential areas. The method was tested on three selected sites in an area of 8.5 km long by 7 km wide and covered by two overlapping (97% overlap) IKONOS images. The images were oriented using rational function models in addition to ground control points. Buildings were identified using an algorithm that utilized the Digital Surface Model (DSM) extracted from the images in addition to the image spectral properties. A digital terrain model was used with the DSM created from the IKONOS stereo imagery to compute building heights. Positional accuracy and building heights were evaluated using corner coordinates extracted from topographic maps and surveyed building heights. The results showed that the average building detection percentage for the test area was 82.6% with an average missing factor of 0.16. When the image rational polynomial coefficients were used to build the image model, results showed a horizontal accuracy of 2.42 and 2.39 m Root Mean Square Error (RMSE) for the easting and northing coordinates, respectively. When ground control points were used, the results improved to the sub-meter level. Differences between building heights extracted from the image model and the corresponding heights obtained through traditional ground surveying had a RMSE of 1.05 m.

California’s Natural Hazard Zonation Policies for Land-Use Planning and Development

California has established state-level policies that utilize knowledge of where natural hazards are more likely to occur to enhance the effectiveness of landuse planning as a tool for risk mitigation. These policies set minimum standards for local government, and range from State designation of regulatory natural hazard zones to requirements that cities and counties include a Safety Element in their General Plan that evaluates their exposure to earthquakes, wildfires, floods, and other natural hazards, and to prepare a federal Local Mitigation Plan to reduce the risk. Such requirements placed on local government are enforced by potential liability for losses for failure to act, and the potential ineligibility for disaster relief funds should a catastrophic event occur. Building codes have been the primary means of mitigating the impact of natural hazards, but continued growth into high-risk terrain and repetitive losses have focused attention to the merits of avoiding harm’s way by means of prudent land-use decisions. Restricting land use can be difficult under the pressures of growth and development. California code exploits knowledge that the cost to adequately protect public safety can influence the type of development that is feasible when considering occupancy (high/low density residential, manufacturing, parkland, etc.) and critical function, such as the need to maintain essential services (police, fire, hospitals, emergency operation centers, etc.). Experience in California demonstrates that a combination of education, outreach, and mutually supporting policies that are linked to state-designated natural hazard zones can form an effective framework for enhancing the role of land-use planning in reducing future losses from natural disasters.

ILLUDAS and PSRM‐QUAL predictive ability in small urban areas and comparison with other models

AbstractThe PC versions of the Illinois Urban Drainage Area Simulator ILLUDAS (ILUDRAIN) and the Penn State Runoff Quality Model (PSRM‐QUAL) are used to predict hydrographs from four relatively small urban sites (5·97 to 23·57 ha), each having a distinct land use designation (commercial, high density residential, low density residential, and highway), and all located in south Florida. The description of the sites and observed rainfall and runoff data were available from the US Geological Survey (USGS), and have been used in the past to validate their model (DR3M). The two models were calibrated and verified using measured rainfall–runoff data (72 storm events for calibration and 26 different events for verification) and measured hydrological characteristics of the four sites. The methodology and input parameters are presented. Predicted hydrographs from the two models are plotted against observed ones and show good agreement. Model performance is evaluated using the mean normalized error computation and scattergrams of predicted versus observed data. A comparison is also made with the results, using the same data and drainage areas, of the following three methods/models tested in previous studies: the runoff curve number (SCS) method combined with the Santa Barbara urban hydrograph method (SCS‐SBUH); the Environmental Protection Agency (EPA) stormwater management model (SWMM); the USGS Distributed Routing Rainfall–Runoff Model (DR3M). The predictions from all models tested in this study showed good agreement with the observed data, with better predictions generally obtained for the more impervious sites. Copyright © 2007 John Wiley & Sons, Ltd.

Land use factors and the risk for child pedestrians

This study investigates the use of land use variables in predicting the number of child pedestrian accident casualties taking Newcastle upon Tyne (UK) as a case study. GIS techniques are used to create spatial models, from which generalised linear models (GLM) are developed over all child accidents and KSI (Killed or Seriously Injured) considering the child pedestrian casualty numbers, land use trip attractors and generators as variables. The results show that that secondary retail and high density residential were the main land use types associated with child pedestrian casualties, in such a way that the former was positively associated while the latter had a negative association. It also found that educational sites were also positively associated with child pedestrian casualties, especially for the KSI.

Effects of suburban development on runoff generation in the Croton River basin, New York, USA

The effects of impervious area, septic leach-field effluent, and a riparian wetland on runoff generation were studied in three small (0.38–0.56 km 2) headwater catchments that represent a range of suburban development (high density residential, medium density residential, and undeveloped) within the Croton River basin, 70 km north of New York City. Precipitation, stream discharge, and groundwater levels were monitored at 10–30 min intervals for 1 year, and stream water and groundwater samples were collected biweekly for δ 18O, NO 3 −, and SO 4 2− analysis for more than 2 years during an overlapping period in 2000–2002. Data from 27 storms confirmed that peak magnitudes increased and recession time decreased with increasing development, but lags in peak arrival and peak discharge/mean discharge were greatest in the medium density residential catchment, which contains a wetland in which storm runoff is retained before entering the stream. Baseflow during a dry period from Aug. 2001–Feb. 2002 was greatest in the high-density residential catchment, presumably from the discharge of septic effluent through the shallow groundwater system and into the stream. In contrast, moderate flows during a wet period from Mar.–Aug. 2002 were greatest in the undeveloped catchment, possibly as a result of greater subsurface storage or greater hydraulic conductivity at this site. The mean residence time of baseflow was about 30 weeks at all three catchments, indicating that human influence was insufficient to greatly affect the groundwater recharge and discharge properties that determine catchment residence time. These results suggest that while suburban development and its associated impervious surfaces and storm drains accelerate the transport of storm runoff into streams, the combined effects of remnant natural landscape features such as wetlands and human alterations such as deep groundwater supply and septic systems can change the expected effects of human development on storm runoff and groundwater recharge.

Relationships of Land Use and Stream Solute Concentrations in the Ipswich River Basin, Northeastern Massachusetts

The relationships of land use/land cover (LULC) on major solute concentrations in stream water were investigated for the Ipswich River basin (404 km2) in northeastern Massachusetts. Stream water was sampled seven times during base flow in 43 first-order catchments and four times in 28 second- and third-order catchments. Regression analysis of the first-order catchment data indicates that NO3−, acid neutralizing capacity (ANC), Cl−, SO42−, and the base cations had positive, mostly exponential relationships with the increasing extent of urban + agricultural area (P < 0.05), whereas dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) had positive, exponential relationships with the increasing extent of wetland + open water (P < 0.05). Solute sources responsible for many of these relationships are human-derived constituents found in septic effluent, fertilizers, and road salts. In contrast to more conservative solutes, concentrations of NO3− in the first-order streams were commonly higher than in those of second- and third-order streams with similar proportions of urban + agricultural land use. Using LULC subclasses (e.g., high density residential), as well as the proportions of LULC in 50, 100, and 200 m concentric zones bordering streams, generally decreased the relationships (r2) determined above. Hence, the disturbed area of the entire subbasin was the best descriptor of streamwater solute concentrations. Potassium concentrations in stream water had stronger relationships than any other ion, yet these explained < 60% of the variability, indicating that there are a number of important ancillary factors that affect streamwater solute composition in the Ipswich River basin.

A COMPREHENSIVE LONG-TERM MONITORING AND ASSESSMENT PLAN FOR THE SAN FRANCISQUITO CREEK WATERSHED

A COMPREHENSIVE LONG-TERM MONITORING AND ASSESSMENT PLAN FOR THE SAN FRANCISQUITO CREEK WATERSHEDThe San Francisquito Creek watershed is located on the broad peninsula south of San Francisco, California. The creek originates in relatively undeveloped hillsides, and flows through agricultural, low density residential, and then highly urbanized land uses before draining into the southerly portion of San Francisco Bay. Stakeholders within the watershed have undertaken a Coordinated Resource...Author(s)Armand RubyGeoff BrosseauSourceProceedings of the Water Environment FederationSubjectSession 7: Habitat Monitoring and AssessmentDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2002ISSN1938-6478SICI1938-6478(20020101)2002:2L.877;1-DOI10.2175/193864702785665878Volume / Issue2002 / 2Content sourceWatershed ConferenceFirst / last page(s)877 - 906Copyright2002Word count320

Soil carbon pools and fluxes in urban ecosystems

The transformation of landscapes from non-urban to urban land use has the potential to greatly modify soil carbon (C) pools and fluxes. For urban ecosystems, very little data exists to assess whether urbanization leads to an increase or decrease in soil C pools. We analyzed three data sets to assess the potential for urbanization to affect soil organic C. These included surface (0–10 cm) soil C data from unmanaged forests along an urban–rural gradient, data from “made” soils (1 m depth) from five different cities, and surface (0–15 cm) soil data of several land-use types in the city of Baltimore. Along the urban–rural land-use gradient, we found that soil organic matter concentration in the surface 10 cm varied significantly ( P=0.001). In an analysis of variance, the urban forest stands had significantly ( P=0.02) higher organic C densities (kg m −2 to 1 m depth) than the suburban and rural stands. Our analysis of pedon data from five cities showed that the highest soil organic C densities occurred in loamy fill (28.5 kg m −2) with the lowest occurring in clean fill and old dredge materials (1.4 and 6.9 kg m −2, respectively). Soil organic C densities for residential areas (15.5±1.2 kg m −2) were consistent across cities. A comparison of land-use types showed that low density residential and institutional land-uses had 44 and 38% higher organic C densities than the commercial land-use type, respectively. Our analysis shows that as adjacent land-use becomes more urbanized, forest soil C pools can be affected even in stands not directly disturbed by urban land development. Data from several “made” soils suggests that physical disturbances and inputs of various materials by humans can greatly alter the amount C stored in these soils.

Effects of residential density on sonoran desert nocturnal rodents

We compared nocturnal rodent distributions among residential developments and in adjacent undeveloped native habitat remnants in Tucson, Arizona during October 1994. We trapped rodents in 2 low density (0.5 houses/ha) developments, 2 medium density (7.5 houses/ha) developments, and in 4 adjacent blocks of undeveloped native habitat using trap lines of 50 snap traps spaced at 2 traps every 10 meters. We compared species abundance, species richness, and total abundance among the 4 site types in a contingency table using a 2-tailed Fisher's exact test, and used post-hoc tests where the null hypothesis of no difference among sites was rejected. We encountered 144 individuals representing 5 species of nocturnal rodents in 1200 trap nights. Of 4 native rodent species, none were captured in medium housing density sites. House mice (Mus musculus) were captured only in medium housing density sites. Total rodent abundance was lower in both the medium density residential and the adjacent undeveloped sites than in either low density or adjacent undeveloped sites. Low density housing must be included in the developing matrix if the full complement of native nocturnal rodents is to be retained in Tucson.

Characterization of urban stormwater runoff

The purpose of this study is to investigate the characteristics of pollutants overflow on storm events, relationships between pollutant load and runoff, and the first flush effect in urban areas. Nine watersheds in the cities of Taejon and Chongju, Korea were selected for sampling and study with different characteristics during the period from June 1995 to November 1997. Runoff and quality parameters such as BOD 5, COD, SS, TKN, NO 3-N, PO 4-P, TP, Pb, Fe, and n-Hexane extracts were analyzed for the development of relationships between runoff and water quality. From the hydrograph and pollutograph analysis, the peak of pollutant concentration preceded that of the flowrate in an area smaller than 100 ha in which impervious area occupied more than 80%. The peak of pollutant concentration, however, was followed by that of flowrate in the watershed in an area larger than 100 ha in which the impervious area was less than 50%. This phenomenon appeared to occur more frequently in the watershed which has the combined sewer systems. In the storm event, the relative magnitude of the pollutants unit loading rate was in the following order; high density residential>low density residential>industrial>undeveloped watershed.