Research on Improving the Safety Margin of Rainwater System

Design for Large Civil Airports

Qing Zhao

China Airport Construction Group Corporation

cacc_zhaoqing@sina.cn

Keywords: Large Civil Airports, Rainwater Systems, Flood Control and Drainage, Rainfall Recurrence Period, Safety

Margin.

Abstract: Rainfall statistics obtained by using a self-recording rain gauge describe the natural law of atmospheric rainfall

occurring, while the uncertainty of atmospheric rainfall makes human beings unable to calculate or forecast

any climate event that is going to happen or the degree of its impact any more accurately. Although the

calculation formula of urban rainstorm intensity deduced from the statistical perspective is included into

relevant design specifications, and the proposed rainfall recurrence period standard is followed to instruct the

rainwater system engineering design, the rainfall recurrence period standard has been determined after

multidimensional consideration to such factors as technology, economy, management and coordination of the

designated age, and also reflects the technical strength of that age, which is also the minimum “threshold” of

design. This paper, combined with construction features and development issues of large civil airports, in

view of rainwater system engineering schemes involved in flood control and drainage of airports, and by form

of case study, puts forward the necessity to improve the safety margin of rainwater system design, and

conducts multidimensional research on how to improve the safety margin of design schemes, enabling the

equipment and facilities of rainwater systems to cope with sudden disastrous weather events, and to a certain

extent, adapt to the upgrade of technical standards in the future.

1 INTRODUCTION

As the global warming effect intensifies, looking at

climate data from the statistical perspective, we find

that many historical records have been constantly

refreshed, occurrence intervals of low-probability

climate events are getting closer, and the uncertainty

in climate is becoming more serious. On July 21,

2012 and July 20, 2016, heavy rainfall never seen

over the past 50 years occurred twice in Beijing, and

some suburban areas even suffered heavy rainfall

even never seen over the past century. These twice of

heavy rainfall not only caused massive waterlogging

on main urban roads, and flooded several flyovers,

but also endangered subway stations, while the

operation of Beijing Capital Airport also faced

challenges, and relied upon its emergency plan to tide

over the difficulty. During the same period, the flood

level of major river basin in China approached or

exceeded the highest water level in history, some

regions suffered a flood disaster, which caused

Refer to long diachronic, flood prevention design recurrence period standard series.

significant property damage to those regions, and as

the flood level rose up, the rainwater self-discharging

system and pumping station drainage system of

several civil airports adjacent to main drainage

channels were also under much pressure. Disaster

weather during the flood season threatens the safe

operation of airports; although the emergency plan of

airports can effectively reduce operational risks, we

should consider how to improve the ability to cope

with more complex climate risks? This requires in-

depth research on a better construction scheme to

avoid similar risks at the stage of airport planning &

design, and meanwhile, establishing an efficient

operation control system and an effective

management coordination mechanism. The focus of

this paper is to study how to improve the safety

margin of rainproof systems of large civil airports

from the perspective of planning, design and

management coordination. It will involve technical

standards, design schemes and multi-department

management coordination.

Zhao, Q.

Research on Improving the Safety Margin of Rainwater System Design for Large Civil Airpor ts.

In 3rd International Conference on Electromechanical Control Technology and Transportation (ICECTT 2018), pages 67-71

ISBN: 978-989-758-312-4

2 DESIGN STANDARD

EVOLUTION

The drainage design of movement areas in China’s

civil airports 30 years ago applied the rainstorm

intensity formula, with its designed recurrence period

of 1 year

(i.e. P=1 year), lower than the design

standard proposed by International Civil Aviation

Organization. At the end of 1980s, the domestic civil

airport engineering design kept in line with the

proposed standard of International Civil Aviation

Organization, and raised such design standard to 5

years (i.e. P=5 years), and meanwhile, gradually

unified the rainwater system design standard of the

terminal area and working area with the movement

area, and the rainwater system design standard of

underpasses already reached 30 years (i.e. P=30

years). Rainwater system design schemes within

airports have become increasingly reasonable. In

recent 20 years, based on several decades of design

experiences, we have successively prepared the

industry standards and technical specifications in line

with the construction features of China’s civil

airports.

3 LAYOUT CHARACTERISTICS

AND PROBLEMS OF LARGE

CIVIL AIRPORTS

Large civil airports refer to airports with multi-

runway systems, with a basic structure of two long-

distance runways enclosing the terminal area, and for

Refer to short diachronic of rainfall, subject to urban rainwater system design storm recurrence standard series.

future

development, new runways will be constructed

successively, which, as far as runway locations are

concerned, will be defined as short-distance runways,

medium-distance runways or long-distance runways

relative to existing runways.

Near runway locations at airside, there are

navigation facilities and airfield lighting facilities.

Airport planning includes the cargo area, aircraft

maintenance area, and working area. In the working

area, there are various energy stations/rooms, such as

switch station and substation of the power supply

system, boiler room and refrigeration station of the

heating & cooling system, pump station of the water

supply and drainage system, regulator station of the

gas system, etc. (fig. 1)

During the airport construction peak in 1990s, all

of new provincial airports in China were planned with

multi-runway systems, and phase one projects mostly

first construct a runway and the relevant terminal area

and supporting facilities. Due to insufficient

experience in planning and construction at that time,

rainwater systems lacked systematic planning, with

inadequate consideration given to subsequent

expansion in the medium and long term.

As the airport construction scale expands,

especially when constructing the second runway, we

would find some problems, such as the connection

between existing facilities and subsequent expansion

facilities is not smooth, particularly in respect of

topographic connection, which caused an over-high

price for subsequent earthwork projects due to lack of

more thoughtful considration in the previous phase;

since in-site and off-site rainwater system schemes

were not smooth in connection, lots of rewiring and

crossing problems arose, leading to an increase of

project costs.

Figure1 diagram of the floor plan of the airport

ICECTT 2018 - 3rd International Conference on Electromechanical Control Technology and Transportation

Besides, the earlier planning and design lacked

systematic research on airport waterlogging issues.

For example, when the runoff amount generated by

rainfall within the scope of airports exceeds the

planned capacity of off-site flood systems, how

should airports resolve waterlogging issues on the

premise of ensuring their own safety? Also, targeted

research has been conducted on the “Sponge Airport”

proposed recently.

4 NECESSITY TO IMPROVE THE

SAFETY MARGIN OF

RAINWATER SYSTEM DESIGN

FOR AIRPORTS

4.1 Large civil airport project cases

The author was lucky to have the opportunity to take

part in the design of Shanghai Pudong Airport

construction project in 1990s, and experienced the

process from project initiation to planning, design and

construction site service. The Pudong Airport project

is near the mouth of the Yangtze river, with long-term

planning of land for at least two runways to be

provided by subsequent land reclamation by filling

the sea in the long run. Due to lack of soil source at

the location near sea and in site per se, airports must

solve the problem of flood prevention in-site and off-

site. Through multiple rounds of scheme

argumentation, and with overall consideration to all

adverse factors at that time, the scheme design

reserved a certain safety margin, and from completion

to present, for 18 years, the rainwater system

operation of Shanghai Pudong Airport remains safe

and sound. The project has used a combination of

multiple schemes to have addressed the rainwater

system and damp/flood prevention issues within

airports.

The new Guangzhou Baiyun Airport is China’s

first project that has constructed two long-distance

runways simultaneously. The flood prevention

standards outside the airport are far lower than the

airport construction standards. Through systematic

analysis, and considering by the project team the

planned conditions of off-site water systems, in areas

restricted by in-site topography, the project uses

forced drainage to raise the water level of the in-site

drainage system, while for off-site open drainage

channels, uses an inverted siphon drain culvert to

cross low-standard watercourse for connection to

flood control and drainage channels with planned

conditions satisfying the requirements of civil

airports. At the time of rainwater system design, when

raising the design standards up to a higher grade for

recalculation, we found the original design scheme

could still realize smooth drainage. By comparing

design calculation results, we find the cost for

improving the safety margin of rainwater systems is

limited, while the reduced degree of heavy rainfall

risks faced by airports is significant (Table 1).

4.2 Necessity to improve the safety

margin of design

Inspirations from the above two cases: the design

standards are rigid and fixed, and multi-dimensional

research schemes can be used to improve the safety

margin of design. With the improvement of overall

strength of engineering construction projects in

China, considering that civil airport projects are a

long-range program, the upgrade of technical

standards is inevitable in the future. Therefore, it’s

necessary and feasible to improve the safety margin

of rainwater system design of large civil airports. The

rainwater system design of airports follows the

specified standards, which can be moderately raised

up to a higher grade at recalculation, and can be

optimized in combination with specific design

conditions.

Table 1: Comparison of Calculation Results on Different Designed Rainfall Recurrence Periods

Designed Rainfall Recurrence

Periods

P=5

years

P=10

years

P=20

years

P=50 years Remarks

Runoff Growth Calculation -

＜16% ＜32% ＜41%

Relative to P=5 years

Project Cost Growth -

＜6% ＜15%

About

20%

Notes: Take the calculation results of rainwater system design of a regional airport for example.

Research on Improving the Safety Margin of Rainwater System Design for Large Civil Airports

5 NEW TECHNOLOGY

APPLICATION AND

GRASPING KEY POINTS OF

SAFETY MARGIN

At present, the newly developed flood control and

drainage simulation software is introduced into new

airport projects in Beijing and Qingdao. The flood

control and drainage simulation software validates

the safety of design schemes, and simulates the

degree of waterlogging within airports under super-

standard rainfall conditions. This points out a

direction for further optimization of in-site rainwater

system planning and design schemes, and also

provides effective support for the operation

department to make contingency plans for the future.

All the new airport projects launched recently are

multi-runway projects. Also, reclaimed land is used

to build artificial islands for construction of multi-

runway civil airport projects, similar to Kansai

International Airport in Japan. With regard to flood

prevention of airports constructed on reclaimed land,

consideration shall be given to the year-by-year rise

of sea levels caused by climate changes.

In the age of information explosion and rapid

technology progress, the rate of technology upgrade

goes far beyond our imagination. Relevant mandatory

specifications and technical standards promulgated

by the state at different time frames are the minimum

“threshold” under social, economic and technical

conditions at that time, so the safety margin of design

proposed herein is based on all-round thinking and

research, and adaptable to the upgrade of technical

standards in the future.

According to research and experience

accumulation on design schemes of more than 20

large civil airport projects, factors that should be

considered for improving the safety margin of

rainwater system design for airports are summarized

as follows:

5.1 Planning

1) Apply the same standard to off-site existing flood

systems or planned drainage watercourse;

2) Transfer in-site rainwater system risks to off-

site water systems to the greatest extent, which is

good for actual operation and operation cost control

of airports;

3) On the premise of observing the design

standards and specifications, make sure to reserve a

safety margin of design;

4) Use the “Sponge Airport” concept to reduce the

pressure of flood systems, but in-site rainwater

system design standards shall not be lowered.

5.2 Details of design schemes

1) Favorable for connection between current

construction and future expansion, ensuring airports

can realize reasonable and effective connection at

different construction sequences;

2) The airport topography design and rainwater

systems shall give consideration to connection with

future construction schemes, and the selection of

rainwater system as self-drainage or forced drainage

shall control the volume of earth works within a

degree acceptable to projects;

3) Various energy and water resource facility

stations, depots, venues and underground entrances

shall reserve a safety margin higher than the design

specifications, all of which shall be designed to

prevent rainwater from flowing backward.

4) To the extent allowed by designed conditions

and controllable investments, the design of rainwater

system pipelines, open channels and box culvert cross

sections shall reserve a certain margin.

5.3 Operation management

1) According to the principle of administration by

region and segment, in-site rainwater systems are

controlled by the airport operation department, while

off-site segments are controlled by the local

watercourse administration;

2) Outlets with self-drainage functions are subject

to dual-brake control as per internal and external

division of labor, wherein, the outer gate is in a

normally open state and controlled by the watercourse

administration, while the inner gate is controlled by

the airport operation department to prevent from

backflow;

3) Build smooth in-site and off-site information

communication channels to exchange data and

information in a timely manner for use of emergency

plans;

4) Clear rainwater system pipelines, channels and

culverts every year, and regularly maintain and

update equipment, facilities and key parts of

rainwater pumping stations.

6 CONCLUSION

With the rapid development of civil aviation

transportation, we should make a forward-looking

ICECTT 2018 - 3rd International Conference on Electromechanical Control Technology and Transportation

master plan for large civil airports to lead each

specific planning, and only those airport construction

schemes of multi-system coordinated development

would be scientific and reasonable. Facing climate

challenges, we shall not stop at bearing, but cope with

the upgrade of technical standards, and employ new

technologies and new philosophies to reduce risks

brought about by climate environments to airport

operation.

REFERENCES:

PRC National Standard Code for Design of Outdoor

Wastewater Engineering GB 50014-2006;

CAAC Code for Drainage Design of Civil Airports

MH/T5036-2017;

ICAO Convention on International Civil Aviation Annex

14 Volume 1 Airport Design & Operation (Sixth

Edition July 2013).

Beijing Municipal Planning Commission, Beijing

Municipal Bureau of Quality and Technical

Supervision. Code for design of stormwater

management and harvest engineering DB11/685-2013.

Laizhen Zhou. The construction and development of China

civil airports(1949-2013). China civil aviation press.

2014.

Guanghui Zhang. China civil airports. China civil aviation

press. 2008.

Beijing Municipal Commission of Housing and Unban-

Rural Development. Beijing municipal engineering

budget quota (pipeline engineering).2017.

Research on Improving the Safety Margin of Rainwater System Design for Large Civil Airports