Water System Evolution and Influencing Factors in Wuhan City

Over the Past 40 Years via Remote Sensing

Shiyu Ruan

College of Resources and Environment, Hubei University, Wuhan, 430000, China

Keywords: MNDWI, Water System Evolution, QGIS, Wuhan.

Abstract: Water systems are an essential component of the earth's ecosystem, providing vital resources for living

organisms and human beings. Therefore, ensuring the health and stability of water systems is imperative for

human life and development. Taking Wuhan City as a case study, this paper utilizes QGIS software to obtain

MNDWI classification maps from four remote sensing images captured in 1985, 1990, 2005, and 2020. It

discusses the rules governing water system evolution and the influencing factors in Wuhan City over the past

four decades. The analysis reveals that rapid urbanization has significantly impacted the river system in

Wuhan during this period. Specifically, there has been a noticeable decline in the overall lake area, which can

be categorized into three stages: a sharp decline from 1985 to 1990, a continuous decline from 1991 to 2005,

fluctuation stage from 2006 to 2020. Urbanization rate directly correlates with its impact on river systems

while macro policies have played a significant role at different stages of change. The natural sedimentation

of lakes leads to the deterioration of lake ecological environment and affects the biodiversity of lakes. Water

resources are reduced, and water environment is deteriorated by filling lakes to make land or constructing

ponds, which leads to excessive development and utilization of land resources. The construction of lake filling

weakens the ecological service function of the lake and destroys the ecological balance. It is noted that the

changes in the lake are caused by multiple factors and evolve with time.

1 INTRODUCTION

The harmonious development of water and city is an

important prerequisite for sustainable urban

development (Gao, 2021; Zhan et al., 2022; Xie and

Ran, 2024). The evolution of urban water system is

very important to cities. Urban water system is an

important source of urban water supply system.

Lakes, rivers and reservoirs provide cities with

drinking, industrial and irrigation water; Urban water

systems can help mitigate the risk of natural disasters,

such as rivers and lakes that play an important role in

flood control and drainage; The urban water system

is conducive to improving the ecological environment

of the city. Water systems such as lakes, rivers and

park water bodies can provide ecological landscapes,

increase urban green space, promote the ecological

balance within the city, and improve the quality of life

of urban residents. The urban water system is an

important part of recreation, such as the park by the

lake, riverside walks and so on. Urban water system

https://orcid.org/0009-0008-4506-6368

can also enhance the image and attractiveness of the

city, many cities by creating the landscape along the

city and supporting facilities around the water system

to improve the image of the city, attract more tourists

and investment. The evolution of urban water system

has an important impact on urban development and

living environment. Cities should pay attention to the

protection and rational utilization of water system,

promote the sustainable development of urban water

system, meet the needs of urban residents for water

resources, and ensure the ecological environment and

sustainable development of the city.

Water system evolution research methods mainly

include geomorphology research, geological survey

technology, numerical simulation, geochronology

and environmental geochemical analysis. These

methods can directly observe surface geomorphic

features, reveal terrain changes, accurately measure

surface elevation, and simulate geomorphic evolution

in different geological periods. However, they are

limited to surface observation and require a large

188

Ruan, S.

Water System Evolution and Inﬂuencing Factors in Wuhan City over the past 40 Years via Remote Sensing.

DOI: 10.5220/0013020900004601

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 1st International Conference on Innovations in Applied Mathematics, Physics and Astronomy (IAMPA 2024), pages 188-194

ISBN: 978-989-758-722-1

amount of field survey and equipment investment,

which may lead to measurement errors and other

problems. With the development of technology, more

scholars gradually use satellite remote sensing means,

such as QGIS, to study the evolution law of urban

water system by processing remote sensing data.

Therefore, based on remote sensing methods, this

paper takes Wuhan City as an example, selects remote

sensing images of Wuhan city in 1985, 1990, 2005

and 2020, uses Normalized water body Index

(MNDWI) for classification, extracts lake water

surface information within Wuhan city, and explores

the water system evolution rules and influencing

factors of Wuhan City in the past 40 years.

2 BACKGROUND OF WUHAN

CITY

As the capital of Hubei Province and a national

central city in central China, Wuhan is located in the

east of Jianghan Plain, between 113°41 '-115 °05' east

longitude and 29°58 '-31°22' north latitude. The total

area of the main urban area is 678 km

(Figure 1).

Wuhan sits at the intersection of China's North-South

fault belt, where the North China Block, the Yangtze

Plate and the southwest Plate meet. Therefore, the

geological structure of Wuhan area is complicated

and the geological resources are rich, but it is also

prone to geological disasters. Wuhan is located in

Jianghan Plain, the terrain is flat, the soil is fertile, and

the central part is scattered with residual hills. The

Yangtze and Han rivers are the two main rivers in

Wuhan. The Yangtze River is the largest river in

China and flows through the center of Wuhan. The

water system of these two rivers forms the main water

network of Wuhan City, which has an important

impact on the geological environment and water

resources of Wuhan City. Lakes are scattered all

around. In the early days of the founding of New

China, there were 127 lakes of all sizes in the main

urban area, whose water area accounted for about 1/4

of its administrative area, ranking first among similar

cities in the country, and known as the "City of 100

Lakes" (Duan, 2013).

With the rapid population growth and economic

development in Wuhan, the development of urban

construction has been accelerated, and the lakes in

Wuhan have fallen into a very embarrassing dilemma:

the number of lakes has dropped sharply; The water

surface area has shrunk sharply; The lake is seriously

silted. Some lakes are gradually swamped, coupled

with soil and water loss caused by human factors,

resulting in shallow lakes and reduced storage

capacity; A large amount of production and domestic

sewage discharge worsens the water quality of lakes

(Wang, 2005). As a key component of the urban

ecosystem, urban lakes provide an important driving

force for sustainable urban development in terms of

climate regulation, flood control and water storage,

eco-tourism and water supply (Yang et al., 2010).

Therefore, it is urgent to research the law of water

system evolution and influencing factors in Wuhan

City.

Figure 1: Regional distribution in Wuhan (Cai et al.,

2017)

3 METHODS

Using remote sensing data, this paper selects four

time points, 1985, 1990, 2005 and 2020, and applies

QGIS to restore water body evolution.

3.1 Data Collection

This paper mainly uses the Landsat series remote

sensing satellite data from the United States

Geological Survey. In order to reduce the influence of

flood season water level changes on lake extraction,

the time nodes of remote sensing data used in this

paper are all from November to March (cold season),

and the image quality is intact without cloud cover

(Zhan et al., 2022). Landset-5 satellite remote sensing

images were used in 1985, 1990 and 2005, and

Landset-8 satellite remote sensing images will be

used in 2020.

3.2 QGIS Modeling

QGIS was used to classify the image data using

Modified Normalized Difference Water Index

(MNDWI). MNDWI is a remote sensing image

processing technology mainly used to distinguish and

extract water information on the surface. MNDWI is

based on the near-infrared (NIR) and short-wave

infrared (SWIR) bands ratio. Because of short-wave

Water System Evolution and Inﬂuencing Factors in Wuhan City over the past 40 Years via Remote Sensing

189

infrared bands, MNDWI can better suppress the

influence of soil background, especially in areas with

sparse vegetation cover or similar soil colors. At the

same time, NIR band has a higher reflection on water

bodies, while SWIR band has a lower response to

water bodies. This makes MNDWI more inclined to

highlight water features, especially in high-resolution

images, so as to obtain four images with more

prominent water features for comparison and

analysis.

4 RESULTS

From 1985 to 2020, the area of 58 key lakes in Wuhan

has shown a downward trend, decreasing from

1034.76 km2 to 687.66 km2, and the water surface

has decreased by 33.54% (347.10 km

). Compared

with 1985, the area of each key lake has shrunk to

varying degrees (Figures 2, 3).

The change in lake area has relatively obvious

stages, which can be roughly divided into three

stages: the first stage (1985-1990) is the sharp decline

of the lake area, which decreased from 1034.76 km

in 1985 to 801.01km

in 1990, a decrease of 233.75

(22%). The second stage (1990-2005) was the

stage of slow decrease of the lake. From 1990 to 1995,

the lake area decreased slightly by about 6 km2, and

from 1995 to 2005, the lake area decreased

continuously, from 794.80 km

to 679.29 km

, and the

decrease area was 115. 51 km

, a decrease of about

15%. The third stage (2005-2020) is the stage of the

fluctuation of lake area, which increased by about

42.97 km

from 2005 to 2014. Although the lake area

decreased from 2014 to 2020, the water area in 2020

was still higher than in 2005. The overall area growth

trend was presented (Figure 2).

IAMPA 2024 - International Conference on Innovations in Applied Mathematics, Physics and Astronomy

190

Figure 3: Change line diagram of water system area

from 1985 to 2020. (Picture credit:Original).

5 DISCUSSIONS

5.1 Water System Evolution Laws

Through data investigation, it is found that the lake

evolution in Wuhan area mainly has the following

characteristics:

Lakes with larger areas are relatively stable, while

lakes with smaller areas are easy to recede. Hanyang

District has the largest decrease in lake area (21.514

) from 1985 to 2020. This is mainly due to the

large number of lakes in Hanyang District and the

relatively small lake area, the extent of natural

siltation of small lakes is serious, which is more

conducive to reclamation, and most of Hanyang

District is a new economic development zone,

resulting in serious lake filling phenomenon caused

by urban construction. The lakes in Wuchang District

and Wuhan district are mainly East Lake, South Lake,

Tangxun Lake, Qingling Lake, Huangjia Lake and

other large lakes, and the lake area is relatively stable.

The period of lake receding in the remote suburbs

(e.g. Dongxihu area) was mainly reflected in the

1980s, and the area decreased by about 12km2 from

1985 to 1990. It may have something to do with the

policies, the construction of the city. In the 1980s, the

economic construction of Dongxihu District became

the focus, and the lake land was continuously filled,

which led to the artificial reduction of the lake area.

From 1990 to 2020, the lake area is relatively stable,

and the lake area decreases by about 2.5 km

. This is

mainly due to the small and small scale of engineering

construction in remote areas, and the lake area is

relatively stable.

In recent 10 years, the lake area in the central

urban area remained relatively stable, while the lake

area in the new urban area decreased sharply. In the

past 10 years, as the Wuhan Municipal government

has strengthened the protection of lakes in the central

urban area, it has carried out corresponding

reconstruction work on the lake shoreline, which has

remained relatively stable, and the lake water area in

the central urban area can be effectively guaranteed.

However, due to a large number of engineering

construction, road building, new factory building, real

estate development, the phenomenon of lake filling

occurs from time to time, resulting in a sharp decline

in the lake area in the new urban area.

5.2 Influencing Factors of Water

System Evolution

As for the reasons for the gradual reduction of the

urban lake area in Wuhan, domestic scholars have

carried out several studies: Wang (2013) believes that

it is mainly caused by the urban economy, the

development and construction of traffic, the

development and utilization of real estate, flood and

blockage, and improper protection and utilization

measures; Duan (2013) pointed out that land

reclamation and fish farming in lakes in the 1970s and

1980s, municipal construction and real estate

development in the 1990s, and the drive of huge

profits in recent years were the main causes in

different stages. Wang (2005) pointed out that the

interest drive in the process of urbanization is the

main reason. Zhang et al. (2010) pointed out that in

the past 100 years, the main reason for the sharp

decline in lake area was the reclamation of lake land.

According to the research results of this paper,

from 1985 to 2020, the three stages of Wuhan water

system change are mainly related to macro policies

and economic development. The first stage: from

1985 to 1990, the lake area decreased sharply. At this

stage, China was in the early stage of planned

economy and reform and opening up, cities entered

the stage of large-scale development and

construction, and urban built-up areas spread rapidly.

Due to its large scale and immovable spatial position,

urban lakes cannot be economically and compact

developed in cities if they are not partially filled with

lakes and lakes and rivers under the requirements of

urban development and construction. In order to build

a good urban development structure, landfilling

frequently occurs, such as between sand lake and East

Lake, sand Lake and Yangtze River. The second

stage: from 1991 to 2005, the lake continued to

decrease. On the basis of the established framework

of early urban development and construction, real

estate developers choose to develop and build

lakeside areas with high ecological value and rich

landscape resources based on the principle of

maximizing economic benefits in the process of urban

development. Moreover, due to the imperfect layout

Water System Evolution and Inﬂuencing Factors in Wuhan City over the past 40 Years via Remote Sensing

191

of the transportation network, it is not enough to

support the urban enclave construction and

development, and the lakeside space in urban built-up

areas is further squeezed. The third stage: from 2006

to 2020, the lake area's fluctuation improves. At this

stage, the urban development is transforming, the city

is renewing, and the urban development area and the

far urban area are expanding. On the one hand, lakes

close to the city center have been restored by lake

connectivity. On the other hand, under the

background of high-quality urbanization, lake

protection is emphasized in the development process

of the new district.

In addition to the impact of macro policies, this

paper, combined with the field investigation, believes

that there are three reasons for lake receding in

Wuhan area:

Natural siltation of lakes occurs due to the

drainage of sloping land, waterlogging in fields

caused by deforestation and overcultivation, leading

to soil and water loss. The sediment carried in the

water is deposited in rivers and lakes. Additionally,

leaves, weeds, and other debris along the river

contribute to constant silt accumulation in riverbeds.

Small rivers and lakes with minimal annual flow

experience faster sedimentation rates, resulting in

yearly silt buildup. Furthermore, inadequate dredging

of many lakes exacerbates the serious issue of river

and lake siltation. As a consequence, most rivers and

lakes are facing extinction as their capacity

diminishes annually. Taking the East Lake in Wuhan

as an example, the scanning of the underwater

topography and silt thickness of the East Lake shows

that the maximum silt thickness of the East Lake is 4

m, the average silt thickness is 1.06 m, and the total

silt volume reaches 35.22 million m

, which is 20%

of the storage capacity of the East Lake.

Lakes are being filled for agricultural or pond

construction to expand cultivated land areas or

promote pond culture. This trend was particularly

prominent during the 1980s when reclamation

projects addressed food shortages and low grain

production. Evidence such as numerous fish ponds

and lower-lying farmland surrounding these

reclaimed areas supports this observation. Taking

Crescent Lake as an example, Crescent Lake is

located in Wuhan City, East and West Lake District

Zumaling Street thirteen branch ditch, also known as

the double lake, in 1958 Zumaling farm, because of

the shape of the lake like the crescent, it was renamed

Crescent Lake, the initial lake area of about 1200 mu,

in the 1980s geological records for more than 700 mu,

now only 460 mu, the area reduced by nearly two

thirds. At present, the lake has become a private

contract lotus pond, surrounded by fish ponds, the

average water depth of about 1 m, poor class V water

quality, the function of the lake is gradually

disappearing, and there is a danger of extinction (Pei

et al., 2018).

Engineering construction to fill the lake. In the

urban development and construction, to solve the land

shortage problem, large-scale lake filling and land

reclamation movement began, especially in plant

construction, municipal engineering and real estate

development. For example, the North Prince Lake is

located at the intersection of Fangcao Road and the

Third Ring Road in Hanyang District. The Third Ring

Road in Wuhan divides the North Prince Lake into

two parts, with an average water level of 20.25 m and

an average water depth of 1.8 m. Before the 1960s,

the water area of the North Taizi Lake was about

11.33km

. In May 1966, Wuhan City (2014)

organized the reclamation of the North Taizi Lake to

build farmland. In 1965, four new farms were built,

followed by Wuhan seed breeding farms, which only

left 0.823 km

, and the water area of the lake dropped

sharply. After the 1970s, the lake area of Wuhan was

relatively stable, and by 2000, the area of North

Prince Lake was 0.705 km

. In the 21st century, the

construction of Wuhan City accelerated the

withdrawal of the North Prince Lake, especially the

Wuhan Third Ring Road passed through the lake with

solid foundation. On the one hand, the road was built

to fill the lake directly; on the other hand, the Third

Ring Road divided the North Prince Lake into two

parts, making the water on both sides unable to flow.

At present, the area of the lake on the northeast side

of the Third Ring Road has gradually shrunk and has

become a pond. Moreover, due to the continuous

filling of the lake by the nearby engineering

construction, the pond area is getting smaller and

smaller, and it has nearly disappeared.

As for the causes of lake retreat, it is generally the

result of the combined action of two or three factors

on the above two factors. For example, Shihu, located

on the outskirts of Wuhan City, reduced its area by

3.817 km

from 1985 to 1990, changed little from

1990 to 2000, and decreased by 2.173 km

from 2000

to 2011. Since 1985, the lake's total area has

decreased by 5.988 km

, or 91%. There is little

engineering construction in this area, and the main

factors of lake retreat are siltation, land reclamation,

pond reclamation and flood control dam construction.

5.3 Suggestions

(1) Through the analysis of the current situation of

lake evolution in the study area, it is found that in

IAMPA 2024 - International Conference on Innovations in Applied Mathematics, Physics and Astronomy

192

recent decades, the number and total area of lakes in

Wuhan have dramatically decreased due to

unreasonable lake filling, pond building, economic

development and natural siltation of sediment, which

will inevitably lead to further aggravation of flood

disasters in Wuhan, and more difficulties in irrigation

and water diversion for residents. The further

deterioration of groundwater resources and the

obvious change of the environment in Wuhan resulted

in a series of consequences. The lake remediation

work in Wuhan City is imminent. this study puts

forward the following suggestions:

(2) Strengthen the supervision of lake protection.

Through the formulation of corresponding laws and

regulations on lake protection, to achieve legal

compliance, strict law enforcement; It is strictly

prohibited to pollute, cut off all pollution sources, and

ensure that clean water enters the lake.

(3) Strictly control the development and

utilization of lakes and their surroundings. Artificial

breeding should be controlled. For lakes in central

urban areas, artificial breeding should be prohibited.

For lakes in suburban areas, the scale of breeding

should be effectively controlled. To prevent any form

of lake filling behavior, especially engineering

construction, real estate development, etc. is strictly

prohibited to fill the lake, and the road through the

lake should be passed in the form of viaduct.

(4) Fully carry out lake improvement and

protection measures. The fish ponds or reservoirs

around the lake should be unified regulation, the lake

and the pond should be integrated, and the water area

of the lake should be expanded; The lake shoreline

should be regulated, the silt should be removed in

time, and the landscape road along the lake should be

built. More artificial canals should be built where

possible to connect lakes in adjacent areas to keep

lakes flowing. As social public resources, the Lake

shoreline and landscape road along the lake should be

independent from the community or private

residential areas.

(5) Cultivate public awareness of lake protection.

Make full use of various channels such as TV,

newspapers, radio and publicity columns to

strengthen the publicity of lake protection and

improve the awareness of lake protection of Wuhan

citizens.

6 CONCLUSIONS

In this study, land use information was extracted from

multi-temporal remote sensing images to

dynamically monitor the temporal changes of lake

area in Wuhan from 1985 to 2020. Since the 1980s,

with the acceleration of urbanization, the water

system in Wuhan has been affected by human

development and utilization, and the water area has

been reduced. During the 45 years from 1973 to 2018,

the area of key lakes in Wuhan City showed a

downward trend as a whole, shrinking by 33.54%

from the original 1034.76 km

to 722.26 km

. Among

them, the phenomenon of lake filling is more

prominent, and some lakes and waters are filled for

urban construction and infrastructure construction,

resulting in the reduction of the area of lakes and

water systems, the destruction of ecosystems and

other problems, and the destruction of urban water

environment.

The influencing factors include macro-policy,

urbanization and industrialization, natural siltation of

lakes, lake filling for land or pond building and

engineering construction for lake filling. It leads to

the deterioration of the ecological environment of the

lake, affects the biodiversity of the lake, reduces the

water resources and deteriorates the water

environment, weakens the ecological service function

of the lake, and destroys the ecological balance.

REFERENCES

Cai, Enxiang, Yaolin Liu, Ying Jing, Lei Zhang, Jiwei Li,

& Chaohui Yin. (2017). Assessing Spatial Accessibility

of Public and Private Residential Aged Care Facilities:

A Case Study in Wuhan, Central China. ISPRS

International Journal of Geo-Information 6(10): 304

Duan Kaimin. (2013). Thoughts on the current situation

and Countermeasures of Wuhan Lake Management /

China Association for Science and Technology, Hubei

Provincial People's Government. Healthy Lakes and

Beautiful China —— The third China Lake Forum and

the 7th Hubei Science and Technology Forum

proceedings. Changjiang Engineering Vocational and

Technical College, 5.

Gao Xinyi. (2021). Association relation of water system

and land use change in mountain cities. Chongqing

University.

Pei Lizheng, Yan Daoping, & Zhang Hongxin, et al. (2018).

A brief analysis of the evolutionary characteristics and

causes of the Lake in Wuhan since 1960s. Geology and

Mineral Resources in South China, 34 (01): 78-86.

The Wuhan Municipal Water Resources Bureau. (2014).

The Wuhan Lake Annals. Hubei: Hubei Fine Arts Press.

Wang Fang. (2005). Based on RS / GIS. Wuhan University.

Wang Zhaolei. (2013). Research on the protection and

utilization of urban lakes in Wuhan since the 1990s.

Environmental Science and Management, 38 (06): 38-

45.

Water System Evolution and Inﬂuencing Factors in Wuhan City over the past 40 Years via Remote Sensing

193

Xie Yuyang, & Peng Ran. (2024). A brief analysis of the

evolution of water environment and urban spatial form

in Wuhan. Building Decoration in China, (08): 89-91.

Yang Guishan, Ma Ronghua, Zhang Lu, et al. 2010.

Current situation and major problems and protection

strategies of lakes in China. Lake Science, 22 (06): 799-

810.

Zhan Qingming, Li Rong, & Zhan Meng, et al. (2022).

Study on the spatial and temporal evolution of lakes in

Wuhan from 1973- -2018 from the perspective of

development policy. Surveying and mapping

geographic information, 47 (06): 1-6.

DOI:10.14188/j.2095-6045.2021318.

Zhang Yi, Kong Xiangde, & Deng Hongbing, et al. (2010).

Research on the evolution characteristics of lakes in

Hubei Province in the past hundred years. Wetland

Science, 8 (01): 15-20.

IAMPA 2024 - International Conference on Innovations in Applied Mathematics, Physics and Astronomy

194