The Environment and Landscape in Motorway Design

Guochao Qian, Shuyu Tang, Min Zhang, Chun Jing

• Publisher: Wiley-Blackwell
• Year: 2014
• Print ISBN: 9781118332979
• eBook ISBN: 9781118332955
• Edition: 1
• Topic: Technologie et ingénierie
• Subtopic: Ingénierie civile

The construction and operation of highways has a significant impact on the environment. While such impact is impossible to avoid, modern highways are constructed and landscaped to minimise these impacts as far as possible.  Good landscaping minimises the impact on those living or working close to the highway, while at the same time regenerating the natural landscape disturbed during construction.         

Using as its background the successful landscape design of the Nanjing-Hangzhou Expressway in Jiangsu Province, China, which opened to traffic in 2007, Highway Landscape Design includes reference to all aspects of the landscaping of highways, including interchanges, embankments, central reservations, bridges, service and toll station areas, and drainage systems. Appropriate consideration is given to the negative impact on the surrounding environment during the process of construction and it discusses the ecological evaluation and conservation strategy for the highway route. China is in some respects at the forefront of highway landscape design as a result of rapid growth and development coupled with the financial resources to implement major infrastructure works, and the concepts, technologies and methods developed for this Expressway provide valuable experience for sustainable development strategies for such infrastructure. 

Chapter 1
Impact of Motorway Construction on the Environmental Landscape and Protection Countermeasures

1.1 Impact on the natural environment

Topography

Motorways are large-scale man-made projects. During their construction, the topography of the surrounding area will be subject to significant impact. For example, before the construction of the Nanjing-Hangzhou Motorway, the area was characterized by beautiful scenery (Figure 1.1). However, since its construction, great changes have happened to the local environment. First, the motorway has occupied a large area of arable land. During Phase I of the project alone, 4329.86 mu (about 288.66 hm²) of land and 2205.3 mu (about 147 hm²) of excavated land was requisitioned; there was a fill volume of 6.1732 million m³ and an excavation volume of 3.1279 million m³. As such a large area of cultivated land was requisitioned, the topography across the construction area of the surrounding area was subject to serious degradation (Figure 1.2), especially the areas of great natural beauty. For example, over 400 000 m³ of stone was excavated from the Donglushan Mountain in Lishui County, resulting in an 80 m high rocky slope surface (Figure 1.3). The construction of the motorway therefore resulted in heavy damage to the local environment. Of course, we can mitigate damage to the local environment by planting vegetation and covering the rock surface with plants, but it is difficult for the environment to revert back to its original condition and therefore destruction to the environment is irreversible. Data show that the area needed to construct a motorway is larger than an ordinary road or railway. In flat and hilly areas, the land occupation ratio of a motorway is usually 8.0∼10.7 hm²/km. Table 1.1 shows the land occupation of the Nanjing-Hangzhou Motorway (Phase I).

Figure 1.1 Picturesque scenery before construction of the Nanjing-Hangzhou Motorway.

Figure 1.2 Excavation resulting in destruction of the landscape.

Figure 1.3 Excavation resulting in a steep slope on the Donglushan Mountain.

Table 1.1 Land occupation area of the Nanjing-Hangzhou Motorway (Phase I) (unit: mu)

Points of origin and destination	Township	Farmland	Commercial forest	Hilly land
K40+480∼K50+480	Zaicheng	1063.7	118.2	23.6
K50+480∼K52+300	Donglu	0	118.7	79.1
K52+300∼K59+156.1	Baima	661.1	103.2	11.5
K59+156.1∼K60+577.77	Gonghe	35.3	0	113.4
K60+577.77∼K61+380	Shangxing	15.8	0	66.8
K61+380∼K68+399.41	Jiuxian	474.4	412.4	45.8
K83+000∼K99+750	Xinchang	1271.9	300.5	137
K99+750∼K103+706.66	Chating	289.7	0	31.8
K103+706.66∼K111+538.29	Chengnan	593	45.6	19.6
K111+538.29∼K112+121.97	Yantou	42.7	3.3	1.4
K112+121.97∼K116+000	Jingtang	691.3	317.7	53.0
K116+000∼K122+126.5	Guijing	190.2	380.3	63.4
K122+126.54∼K130+781.97	Huankeyuan	413	239.4	148.1
K130+781.97∼K146+960	Dingshu	673.9	868.4	293.4
K146+960∼K149+462.23	Fudong	77.7	136.4	45.3
Total		7374.7	3265.8	1168.6

1 mu is equal to ∼666.67 m².

According to Table 1.1, the Nanjing-Hangzhou Motorway occupies an area of 11 808.4 mu (about 787.23 hm²), most of which is farmland and commercial forest, which amounts to 10 640.5 mu (about 709.37 hm²). As a consequence, it brought about not only a devastating effect on the local natural environment, but also had an adverse impact on local agricultural production and socio-economic development.

Soil erosion

Soil is one of the most important factors for the growth of vegetation along a motorway. During motorway construction, quarrying, borrowing earth and spoil grounds will cause soil erosion. The fertility of soil is reduced, changing its physicochemical properties, which makes it more difficult for vegetation to grow and recover. If the soil structure of the land under construction changes due to compaction from machinery or the land being trampled on, the fertility of the soil may not recover for a long time.

Soil erosion destroys the vegetation along a motorway. In turn, the loss of vegetation further exacerbates soil erosion. This vicious circle makes it very difficult for the vegetation to grow and recover. On the other hand, soil erosion causes change in topography, resulting in water and soil loss (Figure 1.4). According to a survey, water and soil loss resulting from motorway construction in Guangdong Province reaches 4.6203 million m³ every year. For example, during the construction of the Ningxia Guyaozi–Wangquanliang Motorway, the area a...

Table of contents

• Cover
• Title Page
• Copyright
• About the Authors
• Introduction
• Chapter 1: Impact of Motorway Construction on the Environmental Landscape and Protection Countermeasures
• Chapter 2: Environmental Landscape Design of Filled and Excavated Sections
• Chapter 3: Interchange Environmental Landscape Design
• Chapter 4: Environmental Landscape Design of the Central Reservation
• Chapter 5: Environmental Landscape Design of Service Areas and Toll Stations
• Chapter 6: Environmental Landscape Design of Bridges and Structures
• Chapter 7: Environmental Landscape Design along the Nanjing–Hangzhou Motorway
• Chapter 8: Environmental Landscape Design of Drainage Systems
• Chapter 9: Ecological Evaluation of Motorway Green Space Systems
• Chapter 10: Vegetation Types and Available Plant Resources along the Nanjing-Hangzhou Motorway
• Chapter 11: Green Landscape Design of the Nanjing-Hangzhou Motorway (Phase II)
• References
• Further Reading
• Index
• End User License Agreement