Rapid Urbanization and Implications for River EcologicalServices Restoration: Case Study in Shenzhen, China

Hongjian Zhou1; Peijun Shi2; Jing’ai Wang3; Deyong Yu4; and Lu Gao5

Abstract: This descriptive case study examines the linkage between rapid urbanization and alterations of river networks. It is intended toaddress ecological services changes in a highly urbanized catchment of Shenzhen, China. Using remote sensing and GIS, urban developmentand the river network between 1980 and 2005 were analyzed. Furthermore, an analysis of vegetation coverage, biological resources value,ecosystems service value, and ecological capital in the highly urbanized Guanlan River subbasin was performed to indicate the ecologicalconsequences of urban sprawl. Results show that rapid urbanization has resulted in a clear decline of drainage density and an obviousecological degradation in river ecosystems. Geographically, there is a shifting of urban land, and the extent of drainage density decreasesfrom the core of towns to the outskirts. The outward expansion of the urban land and the decrease/disappearance of wetland and water bodiesare found to be among the most important driving forces explaining the ecological degradation in river ecosystems in this region of China.Human activities driven by socioeconomic factors should be considered responsible for the degradation of river ecological services. It isirrational to encourage encroachment of river lands in the process of urbanization, and it is also urgent to effectively restore the natural riversto build healthy cities. DOI: 10.1061/(ASCE)UP.1943-5444.0000051. © 2011 American Society of Civil Engineers.

CE Database subject headings: Urban development; Drainage; Ecosystems; Remote sensing; Geographic information systems; China;Rivers and streams; Restoration.

Author keywords: Urbanization; Drainage density; Ecological capital; Remote sensing; GIS; Shenzhen.

Introduction

Land use and cover change (LUCC) and its impacts on the envi-ronment have increased during ongoing global changes (Chase et al.1999; Lambin et al. 2001). The rapid urbanization occurring indeveloping countries plays an important role in global land useand cover change (Han et al. 2009; Kim 2009; Grimm et al.2000; Turner et al. 1990). It also leaves permanent imprints on riverlandscapes (Chin 2006; Baschak and Brown 1995), such as streamsburied underground in storm drains (Elmore and Kaushal 2008),and causes changes to ecological processes on a local and globalscale (Zhang et al. 2008).

Morphological adjustments in the river system due to urban de-velopment can be considered in terms of changes in the channelcross section, reach, and network and basin (Baschak and Brown1995; Gregory 1987a, b; Curran 2008). Data from around the worldhave collectively provided clear evidence for larger channels inurbanizing rivers (Wolman 1967; Gregory et al. 1992; Downsand Gregory 2004). Researchers have also quantified otherurban-induced channel changes that include changes in the size,shape, and composition of river channels (Brown 1970; HeinzCenter 2002; Graf 2003), reductions in sinuosity (Mosley 1975;Whitlow and Gregory 1989), a tendency for bed material to coarsen(Arnold et al. 1982; Finkenbine et al. 2000), and an overall increasein drainage densities (Chin 2006). However, very little research hasaddressed the temporal and spatial patterns of relationship betweenthe extent of urbanization and alterations of a river network.

River systems, just like a well-vegetated humid valley in theurban context, are an important part of complex urban ecosystemsand provide significant ecosystem services (Yong et al. 2010;Finkenbine et al. 2000; Coutts 2009). For instance, the structureand function of headwater ecosystems determine the quantityand quality of water in downstream rivers and lakes (Freeman et al.2007). Despite their importance to ecosystem functioning, littleresearch has focused on the ecological consequences of rapidurbanization on river ecosystems, although many studies havedemonstrated that urban development has various impacts onurban ecosystem structure, function, dynamics, and restoration(McDonnell et al. 1997; Antrop and Van Eetvelde 2000; Pickettet al. 2001; Maestas et al. 2003; Cheng 2005; Schwartz et al.2009). Ecological capital [natural capital (Costanza et al. 1997)],as opposed to social capital, has been a useful index for quantifyingecosystem services (Pan et al. 2005). According to previousresearch (Costanza et al. 1997; Oleviler 2006), ecological capitalincludes natural resources, the physical amounts of renewableand nonrenewable resources, ecosystems that sustain life and

1National Disaster Reduction Center of China, Ministry of Civil Affairs,No.1, Guangbai Eastern Road 6, Chaoyang District, Beijing, 100124,China; and College of Geography and Remote Sensing Science, BeijingNormal Univ., Beijing, 100875, China (corresponding author). E-mail:zhouhj_bnu@hotmail.com

2Academy of Disaster Reduction and Emergency Management,Ministry of Civil Affairs and Ministry of Education, Beijing Normal Univ.,Beijing, 100875, China.

3Key Laboratory of Regional Geography, Beijing Normal Univ.,Beijing, 100875, China; and College of Geography and Remote SensingScience, Beijing Normal Univ., Beijing, 100875, China.

4Academy of Disaster Reduction and Emergency Management,Ministry of Civil Affairs and Ministry of Education, Beijing Normal Univ.,Beijing, 100875, China.

5Key Laboratory of Regional Geography, Beijing Normal Univ.,Beijing, 100875, China.

Note. This manuscript was submitted on February 12, 2009; approvedon August 4, 2010; published online on August 27, 2010. Discussion per-iod open until November 1, 2011; separate discussions must be submittedfor individual papers. This paper is part of the Journal of Urban Planningand Development, Vol. 137, No. 2, June 1, 2011. ©ASCE, ISSN 0733-9488/2011/2-121–132/$25.00.

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provide a wide range of goods and services, and land. In this paper,we used ecological capital and three other indexes to measure theecological services in river ecosystems during urbanization.

In this study, the specific objectives include (1) examining thelinkage between rapid urbanization and alterations of river net-works in Shenzhen, China, and explaining the temporal changein relationships between both variables according to the differentextent of urbanization during the period 1980–2005; and (2)analyzing the change in ecological services in the river ecosystembased on the measurement of ecological capital in the GuanlanRiver subbasin (GLSB) of Shenzhen.

Study Area

Shenzhen is located at the central coastal area in southernGuangdong Province (Fig. 1) and has a total land area of1;949 km2. It has a subtropical oceanic monsoon climate withan annual temperature of around 20–25°. Annual precipitation in-side the study area varies widely from 1,600 to 2,000 mm, of which80% is received during April to September (flood season). Thisarea includes five major rivers: Maozhou River (MZ), GuanlanRiver (GL), Longgang River (LG), Pingshan River (PS), andShenzhen River (SZ), with an area of over 100 km2 for each catch-ment. In addition, there are four river basins that flow directly intothe sea: Pearl River mouth river system (PMRS), Shenzhen gulfriver system (SZRS), Dapeng gulf river system (DPRS), and Dayagulf river system (DYRS) (Fig. 1).

Shenzhen has experienced a rapid rate of urbanization since themid-1980s, and the number of permanent residents has increasedfrom 0.33 million in 1980 to 8.46 million in 2005 (GDSB 2006).This sets a good time frame for studying the relationship betweenurbanization and alteration of the river network.

The GLSB is located in the northwest of Shenzhen; the totalarea of the river basin is 71:2 km2 (Fig. 1). It was selected to assessthe ecological consequence of alterations of the river networkdue to its rapid urbanization. The reasons are (1) between 2000and 2005, the percentage of urban land area increased rapidly, from38% to 45%, while the area of forest land, which played an impor-tant role in the ecological services of the urban ecosystem (Zhang2007), was small and changed only slightly (from 9.2% to 9.8%);and (2) the river network changed extensively: drainage densitydecreased from 0:95 km�1 to 0:69 km�1, and the length shortenedby 18.4 km between 2000 and 2005.

Methodology

This paper can be divided into three parts: (1) urban land and itschange detection, (2) river network extraction, and (3) remotelysensed river ecological services measurement, including themeasurement of vegetation coverage (VC), biological resourcesvalue (BR), ecosystem services value (ES) and ecological capital(EC). Different data sources, processing methods, and accuracyassessments were used in each part.

Urban Land and Its Change Detection

An estimation of urban land and its change was completed using acombination of remote sensing techniques and GIS. Three primarydata sets were used: (1) land satellite images in 1980 [MultispectralScanner (MSS)], 1988 [Thematic Mapper (TM)], 2000 (TM),and 2005 (þETM), and Systeme Probatoire d’Observation de laTerre (SPOT) images in 2005 provided by the China RemoteSensing Satellite Ground Station (CRSSGS); (2) a land-use mapfrom the year 2000 acquired from local government; and (3) 360

reference points for accuracy assessment of land-use classification,which were obtained from a field survey in 2004 and 2005.

The maximum likelihood supervised classification technique(Nirupama and Simonovic 2007) was chosen to apply to the sat-ellite images of different time periods to classify land use into ninecategories: high-density urban land, low-density urban land, paddyfield, forest, shrub and grassland, orchard, wetland, barren land,and water. Due to lack of available land-use maps prior to the1990s, GIS-based topographic contour maps (1∶100;000 acquiredin 1978–1979 and 1∶50;000 acquired in 1987–1989) were used asreferences and to assess the accuracy of urban land maps from 1980and 1988, respectively. A set of 360 data points and SPOT imagery(10-m resolution) were used to rectify the accuracy of the urbanland map from 2005, whereas the urban land map from 2000was rectified by the local government’s land-use map. The accuracyof the land-use maps from the years 2005, 2000, 1988, and 1980were 88.13, 89.62, 86.24, and 85.41%, respectively.

The percent of urban land (Ur) that described the urbanizationlevel of a given region was calculated by the following formula:

Ur ¼ ðSh þ SlÞ=S ð1Þwhere Ur = percentage of urban land in each catchment; Sh = areaof high-density urban land; Sl = area of low-density urban land; andS = total area of the catchment. The catchment boundary inShenzhen was derived from digital elevation models (DEMs)(Colombo et al. 2007) with a resolution of 90 × 90 m; there werenine river basins at a large scale (Fig. 1), and 31 subbasins at asmall scale.

River Network Extraction

River networks in three periods should be extracted in orderto study the relationship between urban land change and rivernetwork change. The river network in 2005 was acquired fromhydrologic modeling based on elevation to delineate the hydrologicflow path automatically from a digital terrain model (DTM)(Elmore and Kaushal 2008); river networks in 1980 and 1988were manually rectified, interpreted, and delineated from “bluelines” (printed river networks on topographic maps) in topographicmaps from 1978 and 1979 (1∶100;000) and 1987 and 1989(1∶50;000), respectively. This method was proved to be appropriate,and it was convenient to complete the network by adding smallvalleys, the presence of which was indicated by crenellations inthe contour lines (Mark 1983). The standard of stream order isshown in Fig. 2.

The method of accuracy assessment consisted of four parts:(1) stream condition (intact or disappeared) of 310 reference pointsobtained from a field survey in 2004–2005 and a general investi-gation (190 reference points) by the Shenzhen Municipal WaterAffairs Bureau of the accuracy of the river network in 2005(Zavoianu 1985); and (2) high-resolution aeromagnetic photogra-phy (1-m resolution) in 1980 and aerial photography (25-cmresolution) in 1988 of the accuracy of the river network. For eachphoto, 500 random points were generated. This method proved tobe appropriate for the accuracy assessment of river network extrac-tion (Zavoianu 1985; Garcia and Camarasa 1999). The accuracyof river network extraction was 93.22% (465 points), 94.18%(470 points), and 93.60% (453 points) in 2005, 1988, and 1980,respectively.

Six morphometric parameters were used to define the character-istics of the river network in different phases: (1) cumulativenumber of rivers; (2) number of river, from first order to finalorder (the fourth order was used in this study); (3) order of rivers;(4) cumulative length of rivers; (5) length of rivers of order one tofour; and (6) basin area. Four indicators were calculated to quantify

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the alternations of the river network: (1) drainage density (Rd),which depicts the cumulative length of rivers per unit of area ina certain basin; (2) river frequency (Rf ), which depicts the cumu-lative number of rivers per unit of area; (3) coefficient of rivernetwork development (Rz), which is the length development ofrivers of order j compared with the final-order river (because the

final-order river is the most stable, and urbanization had poorinfluences on its length due to the field survey of five major riversin Shenzhen; and (4) river network complexity (Rc), which depictsthe structural complexity of the network, taking the length and thestream order into account (GDSB 2006). They can be expressedusing the following formulas, respectively.

Fig. 1. Location of Shenzhen city and (a) land cover and (b) river network in Guanlan River subbasin (GLSB)

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Rd ¼ L=S; Rf ¼ m=S; Rz ¼ Lj=Lm;

Rc ¼ N0 × ðL=LmÞð2Þ

where L = cumulative length of all rivers in a certain basin;S = basin area; m = cumulative number of rivers in the basin;N0 = stream order (four, in this study); Lm = length of final-orderriver; and Lj = length of river of order j.

Ecological Capital Measurement

This study presents a model for EC estimation using remote sensingaccording to previous research (Pan et al. 2005). Some basicparameters of ecosystems are used to adjust the EC according tothe spatial-temporal differences of ecosystem types and qualities,including the land cover type, vegetation coverage, and vegetationnet primary productivity (NPP) of terrestrial ecosystems. Theseparameters are quantitatively measured using moderate-resolutionimaging spectroradiometer (MODIS), land satellite (thematic map-per), and other ancillary data such as precipitation, temperature,solar radiation, and soil properties. Based on the economic param-eters in previously published studies (Costanza et al. 1997; Pan et al.2005; Li et al. 2003) and a few original calculations, the annual ECof the entire terrestrial ecosystems in the GLSB of Shenzhen isquantitatively estimated. The data of precipitation, temperature,and solar radiation were obtained from the Shenzhen MunicipalBureau of Meteorology (SMBM, http://www.szmb.gov.cn/index.jspx), and soil data were obtained from the Shenzhen MunicipalBureau of Land Resources and Housing Management(SMBLRHM, http://www.szfdc.gov.cn).

Four indicators were selected to explore the ecological serviceschange due to rapid urbanization in river ecosystems of GLSB:VC, BR, ES, and EC.

Vegetation Coverage Measurement

Defined as the projected area of vegetation per unit groundarea, VC can be used as an indicator of the quantitative character-istics of vegetation in addition to leaf area index (Gutman andIgnatov 1998). We used the yearly maximum NormalizedDifference Vegetation Index (NVDI) (Hall et al. 1988) and yearlyminimum NDVI to calculate the vegetation coverage. The NDVIwas calculated using the land satellite data with a 30-m resolution.Vegetation coverage can be modeled as the following formula.

The maximum vegetation coverage for each pixel is obtained fromthis model.

VC ¼ ðNDVI� NDVIminÞ=ðNDVImax � NDVIminÞ ð3Þwhere NDVImin and NDVImax = yearly minimum and yearlymaximum, respectively, of the NDVI value at i-pixel.

Biological Resources Value Measurement

The BR is the tangible value of natural resources, such as forest,grass, shrubbery, crops, water and so on. It can be calculated by theNPP (net primary productivity), which was estimated using an im-proved light utilization efficiency model (Pan et al. 2005; Sun andZhu 2000).

BR ¼X

BRðxÞ; BRðxÞ ¼ NPPðxÞ × TðxÞNPP ¼ ε × f 1ðTÞ × f 2ðβÞ × PAR × FPAR� Rc

ð4Þ

BR = annual biological value (yuan) of the study area; BRðxÞ =biological resource value given in RMB yuan ( US$1 equivalentto 7.58 yuan in 2007) of pixel x; NPPðxÞ = annual biologicalresource (gC) of pixel x; TðxÞ = value per unit (yuan·g�1C) of pixelx; Rc = monthly respirated carbon rate; PAR = photosyntheticalactive radiation, ε = maximum efficiency PAR; f 1ðTÞ and f 2ðβÞaccount for the effects of air temperature and soil moisture onassimilation; and FPAR = fraction of PAR absorbed by plantcanopy, as determined by NDVI (Sellers et al. 1994).

Ecosystem Services Value Measurement

Ecosystem services consist of flows of materials, energy, and in-formation from natural capital stocks, which combine with manu-factured and human capital services to produce human welfare(Costanza et al. 1997). In this study, nutrient cycling and storage(NCS); storage and retention of water (STW); soil conservation(SC); and gas regulation (GR), including absorbing carbon dioxideand producing oxygen (Costanza et al. 1997), are regarded asecosystem services. The ES is the sum of the above four values,and the unit is also yuan.

ES ¼ NCSþ STWþ SCþ GR ð5Þ

Ecological Capital Measurement

Within a region, the gross EC is the total value of all ecosystemservices and natural resources of ecosystems. Its value can beexpressed as

EC ¼X

ECðxÞ; ECx ¼ BRx þ ESx ð6Þ

where EC = annual ecological value (yuan) of the study area; ECx =ecological capital of pixel x; BRx = biological resources value ofpixel x; and ESx = ecosystem services value of pixel x.

Other Data Processing

To analyze the spatial distribution of urban development andriver network change (decrease or disappearance), a grid mapwith 500-m resolution was created using the “Generate” tool inARCGIS. Shenzhen could be plotted out on 7,967 grids.

To calculate the river ecological services change due to urbani-zation, buffer areas were created with a width of 30 m at bothsides of the final-order river/stream (fourth-order) and a widthof 15 m, 10 m, and 5 m for third-, second-, and first-order riversor streams, respectively. These buffer areas were considered to be

Fig. 2. Sketch map of stream order used in this study

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the extent of the river ecosystem in GLSB according to the fieldsurvey.

Results and Discussion

Urban Land Dynamics

Fig. 3 shows the urban sprawl in Shenzhen between 1980 and 2005.The area of urban land increased rapidly, especially during 1988–2005, and the percentage of urban land (Ur) changed from 0.6% in1980 to 8.9% in 1988 and 34.5% in 2005. The area of high-densityurban land changed from 0 km2 in 1980 to 1:95 km2 in 1988 and90:1 km2 in 2005; the annual change rate was 0:24 km2 year�1

during 1980–1988 and 5:19 km2 year�1 during 1988–2005. Thearea of low-density urban land also changed rapidly, from11:5 km2 in 1980 to 168:82 km2 in 1988 and 568:18 km2 in

2005; the annual change rate was 19:67 km2 year�1 during1980–1988 and 23:49 km2 year�1 during 1988–2005.

As shown in Fig. 3 and Table 1, there were obvious spatial dif-ferences among the nine basins. There was a higher percentage ofurban land in SZ and SZRS compared with other basins due to theirlocations in the Special Economic Zone of Shenzhen, which wasthe source area of urban development in Shenzhen. By 1988,high-density urban land had appeared in SZ, and there werelarge areas of low-density urban land around the small townsand along the highway in other basins. By 2005, SZ had the highestpercent of high-density urban land among the nine basins, andMZ, GL, and PMRS had more than 40% of their areas coveredby low-density urban land. Owing to the significant percentageof mountain area in DPRS, DYRS, and PS, they had smaller areasof urban land than each of other six basins, especially in 1988and 2005.

Fig. 3. Spatial distribution of urban land in nine basins of Shenzhen in 1980, 1988, and 2005

Table 1. Area and Percentage of High- and Low-Density Urban Land in Nine Basins in 1980, 1988, and 2005

1980 1988 2005

Basin HA=km2 HP=% LA=km2 LP=% HA=km2 HP=% LA=km2 LP=% HA=km2 HP=% LA=km2 LP=%

MZ 0.00 0.00 0.48 0.16 0.00 0.00 17.58 5.79 5.20 1.71 126.04 41.54

GL 0.00 0.00 0.28 0.12 0.00 0.00 15.01 6.17 11.04 4.54 98.33 40.39

LG 0.00 0.00 1.09 0.37 0.00 0.00 20.04 6.78 10.99 3.72 93.45 31.61

PS 0.00 0.00 0.83 0.64 0.00 0.00 2.04 1.56 1.14 0.87 23.53 17.98

SZ 0.00 0.00 3.08 1.80 1.96 1.15 47.38 27.68 30.51 17.82 45.43 26.54

PMRS 0.00 0.00 1.59 0.62 0.00 0.00 31.13 12.17 11.57 4.52 107.64 42.07

SZRS 0.00 0.00 1.29 0.78 0.00 0.00 27.60 16.56 16.65 9.99 51.49 30.89

DPRS 0.00 0.00 1.02 0.56 0.00 0.00 4.94 2.72 2.69 1.48 16.71 9.20

DYRS 0.00 0.00 1.82 1.06 0.00 0.00 2.56 1.49 0.33 0.19 5.49 3.18

Note: MZ = Maozhou River Basin; GL = Guanlan River Basin; LG = Longgang River Basin; PS = Pingshan River Basin; SZ = Shenzhen River Basin; PMRS= Pearl River Mouth rivers system; SZRS = Shenzhen Gulf rivers system; DPRS = Dapeng Gulf rivers system; DYRS = Daya Gulf rivers system. HA, LAdenote the areas of high-density urban land and low-density urban land, respectively;HP, LP denote the percentages of the areas of high-density urban land andlow-density urban land, respectively, based on basin total area.

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Fig. 4 shows the temporal and spatial expansion of urbanland in 1980–2005, based on the grid map with resolution of500 × 500 m. During the period 1980–1988, the early phase ofurban development, urbanization, mainly occurred in the SpecialEconomic Zone and around a few small towns and highways undercomprehensive urban planning, and 5.6% of the total area hadexperienced urban sprawl (Us is above 50%), with 40.6% of theurban sprawl located in SZ. In 1988–2005, the process was the“townization” (urban development in towns) of small towns andalong traffic lines in the region outside the Special Economic Zone.About 21.4% of the total area underwent urban sprawl (Us value ofabove 50%), with 23.7, 20.7, 18.8, 16.4, and 4.5% of urban sprawlland located in MZ, GL, LG, PMRS, and SZ, respectively.

Morphological Characteristics of River Networks

Fig. 5 shows the spatial patterns of river networks in nine basins ofShenzhen in 1980, 1988, and 2005. There was an obvious down-ward trend in river network complexity (Rc), which changed from36.1 to 31.6. The cumulative number and cumulative length of first-and second-order rivers decreased. By 2005, the cumulative lengthof all rivers in the nine basins shortened by 355.4 km (17% of thecumulative length in 1980), and the cumulative number of riversdecreased by 378 (44% of the cumulative number in 1980). Drain-age density changed from 0:84 km�1 in 1980 to 0:65 km�1 in2005, and rivers with a cumulative length of 61.7 km were buriedunderground in storm drains.

Morphological characteristics of the river networks differedamong the nine basins (Table 2). The trends of drainage densityand river frequency change were consistent, which meant that ifthe drainage density showed a downward trend, the river frequencywould decrease in the same period. Drainage density and riverfrequency in SZ and SZRS increased from 1988 to 2005 as a resultof their location in the Special Economic Zone (Fig. 1). The resultsof river network complexity analysis showed that the value inPMRS, SZRS, DPRS, and DYRS flowing directly into the seawas lower than the value in other basins. The value of the rivernetwork complexity in SZ and SZRS decreased during 1980–1988 and then increased during 1988–2005, whereas other basinsdecreased in the two periods. The coefficient of river network de-velopment of first-order rivers decreased, especially in the MZ, GL,LG, and PS basins; on the other hand, in SZ and SZRS, it increasedin two periods owing to the high level of urbanization.

River Ecological Services Degradation as a Responseto Urbanization

At the local and regional scales, river ecological services degrada-tion (RESD) as a response to urbanization can be interpreted withthe following two aspects.RESD Associated with Urban Sprawl and Declining DrainageSystem

Fig. 6 shows the spatial pattern of alteration of river networks inthe process of urbanization in Shenzhen, based on the grid map

Fig. 4. Urban sprawl in nine basins of Shenzhen from 1980 to 1988 and 1988 to 2005

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with resolution of 500 m × 500 m. From 1980 to 1988, 32.3% ofthe total area of Shenzhen experienced the alteration of rivernetworks. About 58.1% of alterations consisted of a decrease indrainage density; 41.9% consisted of the disappearance of streamslocated in the MZ, GL, LG, and PS basins. In 1988–2005, 35.3% ofthe total area of Shenzhen showed the alteration of river networks.About 62.1% of the alterations consisted of disappearance ofstreams; 37.9% consisted of a decrease in drainage density.

The spatial patterns of relationship between drainage densitydecrease, stream disappearance, and urban development (Fig. 7)suggested that urbanization was the most important cause of riverdisappearance and alternation. However, it showed differentcharacteristics in two periods. In 1980–1988, the ring area with adistance of 1–2 km from town was the target area where the extentof decrease to disappearance was the largest; in 1988–2005, the ringarea with a distance of 0–1 km to town became the target area ofdrainage density decline, and the ring area of 4–8 km from town

was the region of stream disappearance. With urban sprawl aroundthe town, the extent of the influenced areas became larger.

These consequences may be attributed to rapid urban sprawl andassociated land-use changes, especially the decline of wetlands.Owing to scarce land resources for urban development, manyminor streams (the first- and second-order streams shown in Fig. 2)and ponds were filled for building. At the same time, some hillswere razed for building, and forest land changed into low- orhigh-urban land. Therefore, within inner urban areas, many smallwater-density bodies vanished or were replaced by regularly modi-fied ditches. Declining drainage systems and sprawling impervioussurfaces weakened or destroyed the ecological services of river sys-tems in urban regions. According to the results of land-use changedetection, the area of wetland in Shenzhen decreased from121:07 km2 in 1980 to 55:98 km2 in 1988 and 17:04 km2 in2005, and the area of forest land changed from 760:11 km2 in1980 to 701:64 km2 in 1988 and 584:70 km2 in 2005.

Fig. 5. River network in nine basins of Shenzhen in 1980, 1988, and 2005

Table 2. Morphological Characteristics of River Networks in Nine Basins in 1980, 1988, and 2005

Rd Rf Rc RZ

Basins 1980 1988 2005 1980 1988 2005 1980 1988 2005 1980 1988 2005

MZ 0.77 0.80 0.71 0.30 0.15 0.15 23.45 31.91 25.14 1.63 0.66 0.15

GL 0.98 0.71 0.69 0.39 0.25 0.17 57.79 29.89 42.14 3.92 0.35 0.60

LG 0.83 1.04 0.66 0.28 0.28 0.13 32.63 25.62 26.12 3.84 0.83 0.66

PS 1.18 1.03 0.56 0.63 0.47 0.12 35.58 20.21 14.31 2.34 0.49 0.00

SZ 0.80 0.70 0.79 0.23 0.15 0.22 18.38 17.74 30.67 0.43 0.29 0.76

PMRS 0.52 0.70 0.56 0.34 0.21 0.16 5.42 3.80 3.66 0.06 0.00 0.00

SZRS 0.43 0.41 0.48 0.19 0.17 0.17 5.74 4.22 9.93 0.15 0.05 0.72

DPRS 1.09 1.10 0.52 0.59 0.68 0.28 9.58 6.75 5.06 1.21 0.27 0.08

DYRS 1.11 1.04 0.84 0.71 0.66 0.46 6.37 5.21 4.81 0.34 0.15 0.16

Note: MZ = Maozhou River Basin; GL = Guanlan River Basin; LG = Longgang River Basin; PS = Pingshan River Basin; SZ = Shenzhen River Basin; PMRS= Pearl River Mouth rivers system; SZRS = Shenzhen Gulf rivers system; DPRS = Dapeng Gulf rivers system; DYRS = Daya Gulf rivers system. Theirlocations can be seen in Fig. 1. Rd = drainage density; Rf = river frequency; Rc = coefficient of river network development; Rz = river network complexity.

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RESD Associated with Irrational Land Use along RiversFig. 8 shows that the EC of river systems in the GLSB decreased

from 2:79 yuan=m2 to 2:34 yuan=m2, resulting in the total value ofEC decreasing from 197.02 million yuan (25.99 million dollars) in2000 to 165.62 million yuan (21.85 million dollars) in 2005. Theother three indicators also showed obvious downward trends: VCdeclined from 47.7% to 36.3%, BR decreased from 12.05 millionyuan (1.59 million dollars) to 6.78 million yuan (0.89 million

dollars), and ES changed from 184.97 million yuan (24.4 milliondollars) to 158.88 million yuan (20.96 million dollars) in2000–2005.

Based on the buffer areas of river networks (seen as the area ofriver ecosystems) in 2000 and 2005, the VC, BR, ES, and EC wereextracted from GLSB (Table 3). Vegetation coverage in the Guan-lan river ecosystem demonstrated a downward trend in 2000–2005because of the decline of the areas of land-cover types with

Fig. 6. Spatial patterns of alterations to river networks in nine basins of Shenzhen from 1980 to 1988 and 2000 to 2005

Fig. 7. Trend of drainage density decrease and stream disappearance in series of ring areas with width of 1 km from 1980 to 1988 and 1988 to 2005

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high-density vegetation coverage, such as rice paddy fields and for-est. However, the percentage of land-cover types with lower densityvegetation coverage, such as urban land and barren land, increased.Mainly depending on some ecosystem types, such as swamp ormarsh, mangrove, river, or lake, and forest according to the pre-vious studies (Pan et al. 2005), the BR declined from 2000 to2005 owing to the significant loss of wetland (swamp, marsh,and mangrove); bodies of water (rivers, lakes, and reservoirs);and forest (Fig. 9). The ES was the sum of the following four eco-logical services: (1) nutrient cycling and storage, which dependedon the forest ecosystem; (2) storage and retention of water, whichdepended on the wetland ecosystem and river or lake ecosystem;(3) soil conservation, which depended on the forest ecosystem; and(4) gas regulation, which depended on swamp or marsh, mangrove,and wetland ecosystems (Costanza et al. 1997). The ES decreaseddue to the area loss of forest, wetland, and bodies of water. Accord-ing to the research of Pan et al. (2005) the value per unit area of EC

is highest in swamp or marsh, followed by river or lake and thenforest. From 2000 to 2005, the percentage of these three land covertypes showed a clear decline, and the EC decrease was inevitable.

The incursion of urban land and the increased percentage ofurban land in the river systems of the GLSB led to the decreaseof wetland, forest land, and paddy fields and resulted in ecologicaldegradation from 2000 to 2005. Rapid urbanization became a mainreason for ecological degradation in river ecosystems.

Implications for River Ecological Services Restorationin Highly Urbanized Regions

Due to the severe consequences of rapid urbanization, restoringriver ecological services has been a very pronounced priority bylocal and provincial governments for political and economicreasons. Thus, much attention should be paid to both technicaland institutional innovations.

Fig. 8. (a) Vegetation coverage; (b) biological resources value; (c) ecosystem services value; (d) ecological capital in GLSB in 2000 and 2005 (withresolution of 30 m × 30 m)

Table 3. Change of Ecological Services in the River Ecosystem of GLSB and Their Relationship with Land Cover Change in 2000–2005

Ecological service Land cover type

Year Item VC (%)a BRa ESa ECa Item URb PFb FTb WLb WTb BLb

2000 ac 41.7 0.13 2.35 2.48 cc 108.7 45.2 3.6 9.9 1.2 17.5

bc 41.7 24.2 442.8 467 dc 55.4 23.0 1.9 5.1 0.8 8.9

2005 ac 31.6 0.07 1.84 1.91 cc 109.0 13.6 2.9 0.5 0.7 24.8

bc 31.6 12.7 320.3 333 dc 64.6 8.1 1.7 0.3 0.4 14.7aVC = vegetation coverage; BR = biological resources value; ES = ecosystem services value; and EC = ecological capital.bUR = urban land; PF = paddy field; FT = forest land; WL = wetland; WT = water bodies; and BL = barren land.ca = value per unit area (yuan=m2); b = total value in river ecosystem of GLSB (104 yuan); c = area of land cover types (ha); and d = percentage ofland-cover type.

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Technically, successful management of drainage systems inurban regions depends on a complete understanding of river eco-systems. Lessons from frequent city floods showed that enoughspace for flooding must be preserved to prevent emergencies onlocal and fine scales. Therefore, an integrated approach is urgentlyneeded. First, flood-risk maps should be produced, which willprovide valuable information to local and senior governmentsfor flood relief (Miguez et al. 2009). Second, based on the spatialpattern of natural rivers in the early periods, some rivers that havedisappeared should be restored, and grass or trees should be plantedalong rivers.

Institutionally, the implementation of policies for river ecologi-cal restoration plays a key role in effective healthy urban regionmanagement. As in other places in China (e.g., Beijing), a top-down approach has dominated regional river ecological servicesrestoration efforts. Land-use planning in the short and long termshas been implemented before urban sprawl, and more attentionhas been paid to maintaining the natural attributes of rivers. InShenzhen, as is typical for rapid urbanization in China, lessplanning was implemented at the early stage of urbanization owingto an ignorance of the role of rivers in healthy cities, and many

rivers were filled. Therefore, on the local and regional levels, strictlegislative actions must be taken to control intensive developmentin river-prone areas. Moreover, local and senior governmentsshould make practicable policies on land-use planning to helpchange the current cultures of dependency on the economic-pronedevelopment mode rather than the double-win (economic and eco-logical) development mode. Both technical and institutional inno-vations related to river ecosystem management in highly urbanizedareas, as described previously, may be useful for other countries,especially for most of the developing countries.

Conclusions

Deepened market reforms and increased globalization have broughtabout profound structural changes not only to the Chinese economybut also to its urban landscape (Xie et al. 2007). Increased urbani-zation has been extensively documented and interpreted (Zhouand Ma 2003). Thus far, scholarly attempts to understand theconsequences of urbanization have concerned the ecological serv-ices in urban ecosystems. River networks, just like an ecologicalbuffer belt, are an important part of complex urban ecosystems

Fig. 9. Urbanization and its impact on rivers, wetland and forest: (a) both sides of Shennan Road before urbanization in 1982; (b) Shennan road afterurbanization in 2005; (c) natural river; (d) river in highly urbanized area; (e) natural wetland; (f) wetland ruined by urbanization; (g) different land-scape at both sides of the Shenzhen river; (h) forest ruined by urbanization

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and provide significant ecosystem services. With rapid urbaniza-tion, rivers in cities have been almost totally altered from their natu-ral states or even obliterated from the urban landscape (Baschakand Brown 1995; Weng 2007). In this paper, remotely sensedimagery, topographic maps, and aerial photos were employed toexamine the linkage between urban development and alterationsof river networks in Shenzhen and to address the ecologicalconsequences in a highly urbanized catchment.

Using a combination of remote sensing and GIS, urban develop-ment and river networks between 1980 and 2005 were analyzed.The percentage of urban land changed from 0.6% in 1980 to8.9% in 1988 and 34.5% in 2005. A small-scale and rapid processof urbanization occurred in the regional central city in the SpecialEconomic Zone of Shenzhen from 1980 to 1988. A full-scale pro-cess of urbanization within the Special Economic Zone and the“country townization” of small towns in the region outside ofthe Special Economic Zone occurred from 1988 to 2005. The rivernetwork in Shenzhen experienced a rapid loss characterized by anincrease in structural simplicity and the restriction of tributaries.The cumulative length of the river network shortened by355.4 km and the cumulative number of rivers reduced by 378;the drainage density decreased from 0:84 km�1 to 0:65 km�1. Geo-graphically, there was a shifting of urban land, and the extent ofdrainage density decreased from the cores of towns to their out-skirts.

Urban development has resulted in losses of farmland, forest,wetland, and bodies of water since 2000 in the GLSB: percentageshave decreased from 23.0 to 8.1, 1.9 to 1.7, 5.1 to 0.3, and 0.8 to0.4, respectively. At the same time, the vegetation coverage de-creased from 41.7 to 31.6%, and the values per unit area of theBR, ES, and EC changed from 0.13 to 0:07 yuan=m2, 2.35 to1:84 yuan=m2, and 2.48 to 1:91 yuan=m2, respectively. The de-crease or disappearance of wetland and bodies of water due to rapidurbanization was found to be one of the most important drivingforces explaining ecological degradation in Shenzhen, China. Hu-man activities driven by socioeconomic factors should be consid-ered responsible for the degradation of river ecological services. Itis irrational to encourage encroachment of river lands in the processof urbanization, and it is urgent to protect and restore the naturalrivers effectively to build healthy cities.

The methodology and most of the data that were used in thispaper could be obtained easily in other regions or countries, withthe exception of topographic maps used to extract the river net-works in different periods (e.g., data about river networks in the1970s and 1980s were extracted based on the related topographicmaps). The defect of the data source, especially the data used inriver networks extraction in this paper, was a weak point that willbe improved or extended in future research. Instead of topographicmaps, other regions or countries could use related data, such ashigh-resolution aeromagnetic photography at the large scale or fieldsurvey data at the small scale.

Acknowledgments

This work was supported by the Key Projects in the NationalScience and Technology Pillar Program (No. 2006BAD20B03,2006BAD20B04), the National Natural Science Foundation ofChina (No. 40801215, 40801211, 40671003). The work of fouranonymous reviewers is greatly acknowledged, which significantlyimproved the quality of this article.

References

Antrop, M., and Van Eetvelde, V. (2000). “Holistic aspects of suburbanlandscapes: Visual image interpretation and landscape metrics.” Land-scape Urban Plann., 50, 43–58.

Arnold, C. L., Boison, P. J., and Patton, P. C. (1982). “Sawmill Brook andexample of rapid geomorphic change related to urbanization.” J. Geol.,90, 155–166.

Baschak, L. A., and Brown, R. D. (1995). “An ecological framework for theplanning, design and management of urban river greenways.” Land-scape Urban Plann., 33, 211–225.

Brown, E. H. (1970). “Man shapes the earth.” Geograph. J., 136,74–85.

Chase, T. N., Pielke, R. A., Kittel, T. G. F., Nemani, R. R., and Running,S. W. (2000). “Simulated impacts of historical land cover changeson global climate in northern winter.” Climate Dyn., 16, 93–105.

Cheng, M. S. (2005). “Anacostia watershed restoration using a low impactdevelopment approach.” Managing watersheds for human and naturalimpacts: Engineering, ecological, and economic challenges proceed-ings of watershed, ⟨http://dx.doi.org/10.1061/40763(178)67⟩.

Chin, A. (2006). “Urban transformation of river landscapes in a globalcontext.” J. Geomorphology, 79, 460–487.

Colombo, R., Vogt, J. V., Soille, P., and Paracchini, M. L. (2007). “Derivingriver network and catchments at the European scale from mediumresolution digital elevation data.” Catena, 70, 296–305.

Costanza, R., et al. (1997). “The value of the world’s ecosystem servicesand natural capital.” Nature (London), 387(6630), 253–260.

Coutts, C. (2009). “Multiple case studies of the influence of land-use typeon the distribution of uses along urban river greenways.” J. UrbanPlann. Dev., 135(1), 31–38.

Curran, J. C. (2008). “A case study of channel change during urbanization:The San Antonio river from 1830–2004.” World environmental andwater resources congress, ⟨http://dx.doi.org/10.1061/40976(316)337⟩.

Downs, P. W., and Gregory, K. J. (2004). River channel management:Towards sustainable catchment hydrosystems, Arnold, London.

Elmore, A. J., and Kaushal, S. S. (2008). “Disappearing headwaters:Patterns of stream burial due to urbanization.” Front. Ecol. Environ.,6, 308–312.

Finkenbine, J. K., Atwater, J. W., and Mavinic, D. S. (2000). “Stream healthafter urbanization.” J. Am. Water Resour. Assoc., 36(5), 1149–1160.

Freeman, M. C., Pringle, C. M., and Jackson, C. R. (2007). “Hydrologicconnectivity and the contribution of stream headwaters to ecologicalintegrity at regional scales.” J. Am. Water Resour. Assoc., 43, 5–14.

Garcia, M. J. L., and Camarasa, A. M. (1999). “Use of geomorphologicalunits to improve drainage network extraction from a DEM: Comparisonbetween automated extraction and photointerpretation methods in theCarraixet catchment (Valencia, Spain).” Int. J. Appl. Earth Observ.Geoinform., 1(3-4), 187–195.

Graf, W. L. (2003). “Summary and perspective.” Dam removal research:status and prospects, W. L. Graf, ed., The H. John Heinz III Center forScience, Economics and the Environment, Washington, DC.

Gregory, K. J. (1987a). “River channels.” Human activity and environmen-tal processes, K. J. Gregory and D. E. Walling, eds., Wiley, Chichester,UK, 207–235.

Gregory, K. J. (1987b). “Environmental effects of river channel changes.”Regulated Rivers: Research and Manage., 1, 358–363.

Gregory, K. J., Davis, R. J., and Downs, P. W. (1992). “Identificationof river channel change due to urbanization.” Appl. Geogr., 12,299–318.

Grimm, N. B., Grove, J. M., Pickett, S. T. A., and Redman, C. L. (2000).“Integrated approaches to long-term studies of urban ecologicalsystems.” BioScience, 50, 571–584.

Guangdong Statistical Bureau (GDSB). (2006). Guangdong statisticalyearbook 2006, China Statistics Press, Beijing (in Chinese).

Gutman, G., and Ignatov, A. (1998). “The derivation of the green vegetationfraction from NOAA/AVHRR data for use in numerical weather predic-tion models.” Int. J. Remote Sens., 19, 1533–1543.

Hall, F. G., Strebel, D. E., and Sellers, P. J. (1988). “Linking knowledgeamong spatial and temporal scales vegetation atmosphere climate andremote sensing.” Landscape Ecol., 2(1), 3–22.

JOURNAL OF URBAN PLANNING AND DEVELOPMENT © ASCE / JUNE 2011 / 131

J. Urban Plann. Dev. 2011.137:121-132.

Dow

nloa

ded

from

asc

elib

rary

.org

by

HA

WA

II,U

NIV

ER

SIT

Y O

F on

05/

01/1

3. C

opyr

ight

ASC

E. F

or p

erso

nal u

se o

nly;

all

righ

ts r

eser

ved.

Han, J., Hayashi, Y., Cao, X., and Imura, H. (2009). “Evaluating land-usechange in rapidly urbanizing China: Case study of Shanghai.” J. UrbanPlann. Dev., 135(4), 166–171.

Heinz Center. (2002). “Dam removal: Science and decision making.”Economics and the environment, The H. John Heinz III Center forScience, Washington DC.

Kim, D. S. (2009). “Development of an optimization technique for apotential surface of spatial urban growth using deterministic modelingmethodology.” J. Urban Plann. Dev., 135(2), 74–85.

Lambin, E. F., et al. (2001). “The causes of land-use and land-cover change:Moving beyond the myths.” Glob. Environ. Change, 11(4), 261–269.

Li, J., Chen, Y. H., and Pan, Y. Z. (2003). “Studies on technology system ofecological property measurement based on remote sensing technologyin western China: The ecological property assessment model based onRS.” Remote Sensing Information, 3, 8–12 (in Chinese).

Maestas, J. D., Knight, R. L., and Gilgert, W. C. (2003). “Biodiversityacross a rural land-use gradient.” Conserv. Biol., 17(5), 1425–1434.

Mark, D. M. (1983). “Relations between field-surveyed channel networksand map-based geomorphometric measures, Inez, Kentucky.” Ann.Assoc. Am. Geographers, 73(3), 358–372.

McDonnell, M. J., et al. (1997). “Ecosystem processes along an urban-to-rural gradient.” Urban Ecosyst., 1, 21–36.

Miguez, M. G., Mascarenhas, F. C. B., de Magalhaes, L. P. C., andD’Alterio, C. F. V. (2009). “Planning and design of urban flood controlmeasures: Assessing effects combination.” J. Urban Plann. Dev., 135(3), 100–109.

Mosley, M. P. (1975). “Channel changes on the River Bollin, Cheshire,1872–1973.” East Midland Geographer, 6, 185–199.

Nirupama, N., and Simonovic, S. P. (2007). “Increase of flood risk due tourbanisation: A Canadian example.” Nat. Hazards, 40, 25–41.

Olewiler, N. (2006). “Environmental sustainability for urban areas: The roleof natural capital indicators.” Cities, 23, 184–196.

Pan, Y. Z., Shi, P. J., Zhu, W. Q., Gu, X. H., Fan, Y. D., and Li, J. (2005).“Measurement of ecological capital of Chinese terrestrial ecosystembased on remote sensing.” Sci. China Ser. D, 48, 786–796.

Pickett, S. T. A., et al. (2001). “Urban ecological systems: Linkingterrestrial ecological, physical, and socioeconomic components ofmetropolitan areas.” Ann. Rev. Ecol. Syst., 32, 127–157.

Schwartz, J. S., et al. (2009). “A monitoring and assessment framework toevaluate stream restoration needs in urbanizing watersheds.” World

environmental and water resources congress, ⟨http://dx.doi.org/10.1061/41036(342)375⟩.

Sellers, P. J., Tucker, C. J., and Collatz, G. J. (1994). “A global 10 by 10NDVI data set for climate studies. Part 2: The generation of global fieldsof terrestrial biophysical parameters from the NDVI.” Int. J. RemoteSens., 15, 3519–3545.

Sun, R., and Zhu, Q. J. (2000). “Distribution and seasonal change of netprimary productivity in China from April, 1992 to March, 1993.” ActaGeographica Sinica, 55, 36–45 (in Chinese).

Turner, B. L., Clark, W. C., and Kates, W. C. (1990). The earth astransformed by human action: Global and regional changes in thebiosphere over the last 300 years, Cambridge University Press,Cambridge, U.K..

Weng, Y. C. (2007). “Spatio-temporal changes of landscape pattern inresponse to urbanization.” Landscape Urban Plann., 81, 341–353.

Whitlow, J. R., and Gregory, K. J. (1989). “Changes in urban streamchannels in Zimbabwe.” Regulated Rivers, 4, 27–42.

Wolman, M. G. (1967). “A cycle of sedimentation and erosion in urbanriver channels.” Geografiska Annaler Series A, Physical Geography,49(2/4), 385–395.

Xie, Y. C., Fang, C. L., Lin, G. C. S., Gong, H. M., and Qiao, B.(2007). “Tempo-spatial patterns of land use changes and urbandevelopment in globalizing China: A study of Beijing.” Sensors, 7,2881–2907.

Yong, Y., Zhang, H., Wang, X. R., and Schubert, U. (2010). “Urbanland-use zoning based on ecological evaluation for large conurbationsin less developed regions: Case study in Foshan, China.” J. UrbanPlann. Dev., 136(2), 116–124.

Zavoianu, I. (1985). Morphometry of drainage basins, Institute ofGeography, Bucharest, Romania, 238.

Zhang, H., Ma, W. C., and Wang, X. R. (2008). “Rapid urbanization andimplication for flood risk management in hinterland of the Pearl RiverDelta, China: The Foshan study.” Sensors, 8, 2223–2239.

Zhang, W., Zhang, X. L., Li, L., and Zhang, Z. L. (2007). “Urban forestin Jinan city: Distribution, classification and ecological significance.”Catena, 69(1), 44–50.

Zhou, Y., and Ma, L. J. C. (2003). “China’s urbanization levels: Recon-structing a baseline from the Fifth Population Census.” China Q.,173, 176–196.

132 / JOURNAL OF URBAN PLANNING AND DEVELOPMENT © ASCE / JUNE 2011

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nloa

ded

from

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elib

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by

HA

WA

II,U

NIV

ER

SIT

Y O

F on

05/

01/1

3. C

opyr

ight

ASC

E. F

or p

erso

nal u

se o

nly;

all

righ

ts r

eser

ved.