3d environmentalimpact assessment(eia)

Project WATERMAN Public Lecture Series

3D Environmental Impact Assessment (EIA)

香港近海水質預報及管理系統 — 公開講座系列

三維環境影響評估

Project WATERMAN Public Lecture SeriesReal-time Beach Water Quality Forecast for Hong Kong香港近海水質預報及管理系統 — 公開講座系列

香港海灘水質實時預報系統

Opening Address 開幕辭

Deputy Director of Environmental Protection, HKSAR香港特別行政區環境保護署副署長

Mr. Benny Wong, JP黃耀錦太平紳士



Lecture Title:

3D Environmental Impact Assessment (EIA) 講座主題:


Speakers: Prof. Joseph Hun-wei Lee & Prof. Wenping Wang

Principal Investigator and Co-Principal Investigator of Project WATERMAN

講者：

李行偉教授及王文平教授Project WATERMAN 項目負責人及副負責人

Outline - 概要

Why environmental impact assessment (EIA)? Why 3DEIA? - 為什麼需要環境影響評估？為什麼三維？

Challenges of quantitative EIA 定量環境影響評估的挑戰

NOVA – a robust tool for 3DEIA三維環境影響評估的可靠工具

Applications and case studies 實際應用

Concluding remarks - 結語

Advanced computer graphics (CG)techniques - 先進的電腦圖形技術

Oyster bed養蠔區

Coral reef珊瑚礁

Wetland濕地

Marine park海岸公園

Habitat of Chinese dolphin

中華白海豚的棲息地Secondary contact

zone 次級康樂活動區

Fish farm海魚養殖區 Beach海灘

Hong Kong’s coastal waters - 豐富的海洋資源

Main pollutant discharges - 主要污染源

Domestic sewage 生活污水

Stormwater 暴雨沖刷 Thermal discharge 冷卻水

Industrial effluent 工業廢水

Discharge from paper mill on Yangtze

Accidental pollutant discharges - 突發污染災難

Pipe damage

Closure of 5 beaches in Tuen Mun July 1997

屯門海底排污管爆裂事件

Chemical spill in Songhuajiang River after an explosion November 2005

Chemical spill

松花江化學原料泄漏事件

Oil spill

78000 m3 of crude oil discharged from ruptured oil well in

Gulf of Mexico April 2010

墨西哥灣原油

泄漏事件

Toxic spill

西江山埃泄漏事件Toxic cyanide spill in

Xijiang River March 1997

Water pollution problems水污染問題

Beach closure海灘關閉

Ecological threat生態破壞

Red tide紅潮

Sewage slick污水擴散

Dissolved oxygen level 含氧量

Unionized ammonia level 非離子氨濃度

Bacteria level 細菌濃度

Toxic organic pollutants 有毒有機物

Endocrine Disrupting Compounds 內分泌干擾物

Examples of Marine Water Quality Objectives (WQOs) - 海水水質指標

Parameter -水質參數 WQO #1

Physical(物理性)

Dissolved oxygen (bottom) 底層溶解氧

> 4 mg/L #2

Biological(生物性)

E. coli 大腸杆菌

< 610 counts/100mL #3

Chemical(化學性)

Unionized ammonia非離子氨

< 0.021 mg/L #4

Nutrient(營養物)

Total inorganic nitrogen 總無機氮

< 0.1 mg/L #4

#1: Tolo Harbour Water Quality Control Zone#2: 90 percentile#3: annual geometric mean#4: annual mean

Why environmental impact assessment (EIA)?為什麼需要環境影響評估?

• Determine and quantify environmental impacts due to development activities - 確定和量化環境污染問題

• Water quality management (standards, regulations) - 水質管理

• Project design and decision making - 項目設計及方案選擇

• Disaster mitigation and response - 災難風險管理

Avoid, minimize and mitigate adverse impacts in a most sustainable and economical manner

用最可持續發展的和最經濟的方式來避免、減小、舒緩環境污染影響

What is EIA ?什麼是環境影響評估?

= Treat the environment like a bucket into which waste may be deposited until it is full?將整個環境當做一個垃圾桶，不斷將污染物掃入，

卻只顧桶內是否還有空間容納“垃圾”

Tolo Harbour Effluent Export Scheme吐露港污水輸出計劃

E. coli level HighLow

Sewage outfall

Tolo Harbour

Kowloon

New Territories

HK Island

Tai Po STW

Sha Tin STW

Victoria Harbour

(After 1998)

Kowloon

Hong Kong Island

Discharge of exported effluent

例子1：Avoidance

Harbour Area Treatment Scheme (HATS)Treatment level and discharge location

淨化海港計劃- 污水處理程度及排污選址

Stage 1：Commenced in December 2001

(Chemically Enhanced Primary Treatment)強化一級污水處理

Disinfection (chlorination):

Started in March 2010 污水消毒處理 (氯化)

Stage 2A : Commenced in 2014

例子2：Minimization

Optimisation of disinfection (chlorine) dosage消毒劑(氯)用量的最優化控制

SAL: 10 100 1000 10000E. coli (counts/100 mL)

With disinfection 有消毒

Kowloon

Hong Kong Island

815000 820000 825000 830000 835000

SAL: 10 100 1000 10000E. coli (counts/100 mL)

Without disinfection 無消毒

Kowloon

Hong Kong Island

However, too much chlorine is toxic (有毒) to aquatic life !Chlorination byproducts is carcinogenic (致癌) to humans !Can we real-time control the disinfection dosage?

能否實時控制消毒劑(氯)的用量 ?

例子3：Mitigation

Key concept in EIA: Assimilative Capacity - 環境同化能力

The environment has a self-purification capacity (自淨) by a series of physical, chemical and biological processes.

Physical - 物理淨化(mixing, dispersion,

sedimentation)

Chemical - 化學淨化(oxidation-reduction,

neutralization)

Biological - 生物淨化(die-off, degradation,

decomposition)

Small volume of pollutant

Huge receiving water body

Raw sewage 未處理污水 Secondary

treated 經二級處理後

污水中的細菌含量

Initial dilution 初始稀釋後

Secondary dilution

and decay後續稀釋及衰亡

Natural environment

Treatment level

• Site-specific 因水文及地貌條件而異

• Activity-specific 因活動而異e.g.: Sewage discharge, thermal discharge, reclamation

• Time-dependent 隨季節、潮相、時間而定

Assimilative capacity - 環境同化能力

Kowloon

Hong Kong Island

Tidal flushing Assimilative capacity

ToloHarbour

New Territories

潮汐沖刷環境同化能力

0.02 -0.03 m/s

月份

River flow河流流量

NH4氨氮

Waste assimilative capacity is dependent on the river flow

Predicted monthly-averaged NH4 levelat Qiaotou, East River

東江橋頭的月平均氨氮含量和河流流量

If the assimilative capacity is exceeded, water pollution problems arise!

當污染物的排放量超過環境同化能力，便會產生水污染問題！

By 2030, 60% of the world’s population will be living in towns and cities - 全球60%為城市人口


• Determination of the impact and the sphere of influence環境影響及其邊界的確定

• Complex marine environment in Hong Kong香港複雜的海洋環境

• Complicated 3D hydrodynamic mixing and transport複雜的污染物環境水流混合機理

• Need for robust modelling tools可靠的評估模型工具

• Effective public engagement有效的公眾參與

典型的旱季

Complicated tidal currents - 複雜的潮汐流

1. Tidal currents 潮流

2. Pearl River discharge 珠江流量

3. Monsoon induced coastal currents 受季候風影響的海洋環流

Factors influence Hong Kong’s hydrography影響香港水文狀況的因素

Environmental discharges in the form of buoyant jets污染物以各種浮射流的形式在水環境中排放

Single jet 單孔排放

Dense jet 海水化淡廠鹽水 Sediment jet 泥沙排放

Multiple jet 多孔排放

• 在許多情況下，我們需要對污染排放的危害作出評估，以確定某一指定水域的水質是否達到指標。

• 排放物在渦流作用下被不斷地混合、稀釋和分解, 混合的情況決定於污水出流特性（污水量、密度、排放速度和方向、擴散器的設計）和環境條件（密度、流速、流向和鹽度及溫度的垂直分佈）。

• 適當的污水處理和排污的設計和選址，可以充分利用環境的

自然淨化能力，從而降低對環境的影響。

Scientific management of water quality relies on quantitative EIA

科學化水質管理有賴於定量環境影響評估

Near field + Intermediate field 近場 + 中場 Far field 遠場

Length: km

Time: hr

Length:10-500m

Time: min

Side view

Plan view

Mixing processes - 污染物與環境水流的混合機理

污染帶深海排污口環境水流

污染帶

海灘

海灘

卷吸

不同長度及時間比尺

湍流擴散細菌衰減

Tidal current transporting pollutants to nearby beaches

Far field transport - 遠場輸送

Spreading of bottom density current 海水化淡廠高濃度鹽水在海床的浮力擴散

Ambient current

Near field 近場 ~ 10m Intermediate field 中場 ~ 100m

NOVA – a robust tool for 3DEIA三維環境影響評估的可靠工具

Near-far field coupling近場-遠場無縫耦合

Hydrodynamic and transport model三維水動力模型

Project WATERMAN 三維環境影響評估系統

General Lagrangian 3D buoyant jet model- JETLAG/VISJET 通用的近場浮射流模型

NOVA地理信息系統和可視化技術

1

2

3

JETLAG/VISJET - 近場浮射流模型

Experiments 實驗 + numerical modeling 數值模型

PIV LIF CFDVisualization

Extensive laboratory and field validation 大量基礎研究、實驗及實地驗証

Vortex pairAdvected line thermal

DESA prediction模擬結果

GIS-based

Seamless and robust 3D prediction from near to far field 可靠及無縫的從污染近場至遠場的三維模擬

Full integration with GIS data and advanced visualization 結合地理信息系統和先進可視化技術

Effective communication and public engagement 有效的溝通及公眾參與

NOVA – Project WATERMAN 3DEIA system

Internet-based

Numerical harbour

Laboratory observation實驗觀測

3D Digital Terrain Model and GIS 三維數值地形模型及地理信息系統

Applications and case studies 實際應用

Application Examples - 實際應用

• Prediction of water quality at the locations of sensitive receivers 預報敏感受納水體的水質

• Determination of mixing zones界定污染物的混合區

• Submarine outfall design設計深海排污系統

• Estimation of the environmental risks估計環境風險

• Unraveling the causes of accidental pollution disasters解構突發污染災難的原因

1. Defining the initial mixing zone of wastewater discharges界定污染物的初始混合區

Length of initial mixing zone =190m

Ua = 0.4m/s

Length of initial mixing zone = 20m

Ua = 0.15m/s

Multiple discharges from a rosette diffuser

The length of initial mixing zone?

多個浮射流的玫瑰流擴散器

2. Impact of Sai Kung increased sewage discharge on seawater salinity

西貢污水處理廠第二期改善工程(增加污水排放量)對附近海水鹽度的影響

Will salinity drop significantly?

Will fish production be reduced?

Sai Kung outfall西貢排污口

Ma Nam Wat麻南笏

Kiu Tsui橋咀

Hap Mun廈門灣

Fish farm 海魚養殖區 Beach 海灘

Trio三星灣

PM3

PM2

Marine water quality monitoring 水質監測站

牛尾海

Sai Kung outfall

Ma Nan Wat

Kiu Tsui

Salinity (ppt)

32 33 34 35313029

Outfall 污水排放口

Salinity (ppt)Salinity at Ma Nam Wat

麻南笏海魚養殖區

海水鹽度

Salinity (ppt)

Salinity at water surface of the outfall 污水排放口正上方的海水鹽度

麻南笏

西貢排污口

橋咀

1 – 2 pptdifference only!

Outfall (Option B)

In more open water (existing site)

3. Sai Kung Secondary Sewage Treatment WorksOptimizing the outfall location - 排污選址

E. coli level (counts/100 mL)

E. coli level

HighLow

100 times higher bacteria level!!

Close to a public pier


Outfall (Option A)

水質監測站


180WQO


WQO 610

E. coli level

HighLow

Kiu Tsui

Sai Kung outfall

Impact of secondary treated sewage discharge upon a beach based on E. coli排放二級處理後的污水對附近海灘水質的影響

PM3

Beach 海灘

Marine water quality monitoring 水質監測站

橋咀

西貢排污口

Time (day)

Sur

face

sal

inity

(ppt

)麻南笏海魚養殖區

海水鹽度

Riv

er d

isch

arge

(m3 /s

)Time (day)

4. Impact of rain storm event - 暴雨帶來的環境影響

Time (day)

E. c

oli (

coun

ts/1

00 m

L)

Salinity (ppt)

32 33 34 35

三星灣海灘大腸桿菌濃度

5. Pillar Point sewage outfall damaged by a dredger - 望后石海底排污管爆裂 (1997)

• ~3-4 am on 8 July: a dredger damaged the outfall pipeline挖泥船鑿穿海底排污管

• ~11-12 am on 8 July: extremely high E. coli level was measured at nearby beaches屯門海灘大腸桿菌濃度超標

• 11 July: beach closure 海灘關閉

Damaged Pillar Point Outfall爆裂的海底排污管

Normal operating condition 正常狀況(70 vertical jets, total flow = 1.46 m3/s, depth 10 m)

Damaged outfall

pipeline near shore

近岸爆裂的兩個大孔

Two large punctured holes in outfall pipe (depth 5 m, total flow = 0.98 m3/s)

Is the high bacteria level caused by the dredger? 挖泥船鑿穿海底排污管是否導致細菌濃度上升的原因?

24

180

610

1

10

100

1000

10000

5-Jul 6-Jul 7-Jul 8-Jul 9-Jul 10-Jul 11-Jul

NormalBroken

.co (cou ts/ 00 ) Go de

After damage 爆裂後

E. coli level at Golden Beach

黃金泳灘的大腸杆菌濃度

(counts/100 mL)

正常

爆裂

6. Real-time control of disinfection dosage; Harbour Area Treatment Scheme實時控制消毒劑量 – 淨化海港計劃

Fate and transport from the submarine outfall to sensitive receivers

消毒消毒消毒

潮位

HATS outfall

6h

停止停止

6h

Optimal real-time controlled chlorine dosage最佳實時控制消毒劑(氯)用量

Can we work with nature to optimize chlorine dosage

while still protectingTsuen Wan beaches?

我們能否充分利用環境的自然淨化能力來實時控制氯的用量，同時保護荃灣海灘

的水質？

過量的氯毒害海洋生物氯的副產品致癌

漲潮

退潮

0.001

0.01

0.1

1

10

100

1000

10000

9-Jun 11-Jun 13-Jun 15-Jun 17-Jun 19-Jun

Full DisinfectionNo DisinfectionIntermittent Operation

E.coli (counts/100mL)

610

180

24

WQO

Predicted E. coli level at Gemini Beach 雙仙灣的大腸杆菌濃度

With a careful control of disinfection dosage, beach water quality can meet WQO practically all of the time 利用海流特性進行間歇性消毒，從而舒緩消毒劑對環境的影響

Over-protectionPoor water quality

Summary (1)

• Assimilative capacity of water bodies depends significantly on environmental conditions 環境同化能力隨自然環境變化

• EIA requires fundamental scientific research that spans several disciplines環境影響評估基於大量可靠的跨學科研究、理論和實驗

• The NOVA system crystallizes from decades of work in environmental hydraulics and computational engineering. It has been thoroughly validated against laboratory and field data.基於多年來先進的環境水力學和電腦圖形技術，Project WATERMAN 開發了一個可靠的三維環境影響評估工具NOVA (大量基礎研究、實

驗及實地驗証)

• Combining with an advanced GIS system, NOVA provides,– a powerful tool for quantifying, and hence, the avoidance,

minimization and mitigation of different forms of pollution in water bodies

– effective communication to decision-makers, engineering professions and general public the risks and management of water pollution and thereby raising their understanding and appreciation for EIA as a valuable tool to protect the environment

結合了地理信息系統和互聯網技術，NOVA提供有效的公眾參與，從而實現“避免，減小，舒緩”的環境影響評估精神

Summary (2)

Advanced computer graphics(CG) techniques

先進的電腦圖形技術

Advanced Computer Graphics (CG)Techniques - 先進的電腦圖形技術

• There are 2 systems– NOVA: a 3D GIS-integrated software running

on a single computer, for 3D EIA– Internet EIA: a web-based delivery system for

NOVA’s scenarios, for public engagement• Challenges

– Both systems deal with visualization of huge GIS-data as well as simulation results in 3D

– Different challenges, different approaches

Data to Visualize 需要可視化的數據

Terrain (tens of gigabytes)

Far-field Simulation Results(up to a few gigabytes)

Near-field jets(up to a few hundred megabytes)

The NOVA Software, NOVA 軟件

• NOVA is a software used mainly by professionals using high performance computers

• Like a CAD software, but operates in full 3D• Terrain data cannot be fitted into the memory so

it must first be simplified for efficient display. Some details are lost in the process.

• Far-field and near-field jet data are rendered directly. Programmable display card (GPU) is used for efficient interpolation, which is vital to smooth animation.

NOVA in Action, NOVA 的操作

CG Challenges in Internet EIA,電腦圖形技術在互聯網 EIA 上的挑戰

• Used by the public with different kinds of computers so high performance computer is not guaranteed

• Need to support most visualization functions in NOVA, like full 3D GIS integration, interactive viewing, data-interrogation etc.

• Gigabyte size data is not practical to be distributed directly via the Internet

CG Solution for Internet EIA互聯網 EIA上電腦圖形技術方案

• Separate handling for static and dynamic data– Static data – GIS/Terrain data– Dynamic data – Far-field concentration field data

and near-field jet data

• Static Data – Server-assisted rendering

• Dynamic Data – Video streaming

Internet EIA Schematics互聯網 EIA 技術方案結構圖

MultipleRenderingServers

ImageCompositing

Server

Clients

Partial images

VideoStreaming

ServerMovie filesSim. Results

Conversion

INTERNET

Video stream

Whole image

ControlServer

On-demandData

Data Interrogation Service

Static Data

Dynamic Data

Whole image

Server-assisted Rendering伺服器協助式渲染

• Client does not require high-res terrain data• Server renders image directly for client for each

“steady” viewpoint• Only images are transmitted to client• No excess terrain details are transmitted• Rendered image is usually returned within 1 sec• Complex render algorithms are implemented in

servers only so client is very light weight

Video Streaming for Visualization用於可視化上的視頻流

• Accurate dataset is down-sampled to perception level accuracy. i.e. only to maintain a correct perceived color coding at a pre-defined resolution. Data size is greatly reduced.

• Accurate data is only sent during data interrogation.• Using video compression to further reduce file size.• Using streaming technology to send data at a

steady rate to prevent sudden network traffic surge.

Internet EIA Characteristics互聯網 EIA 的特點

• Bandwidth requirement similar to watching Youtube video, i.e. no large file download

• Instantaneous high resolution terrain display• Higher terrain quality than local visualization• Very low client computation power requirement

Internet EIA

NOVA

Internet EIA in Action,互聯網 EIA 的操作

• As illustrated by the applications examples, a robust 3Dwater quality forecast and visualization system has beendeveloped to quantify the impacts and environmental risksof Infrastructure projects and communicate the predictedimpact to the stakeholders effectively.

• It includes two key components:1) the modelling and visualization system (NOVA) serves

as an EIA tool for professionals;2) the internet-based interactive visualization system that

delivers realistic 3D visualization of simulated resultsover the Internet for easy public access.

Concluding Remarks - 結語

To treasure our coastal water resourcesby first understanding them

Please visit our WATERMAN webpagewww.waterman.hku.hk

for more details



Q and A 問答環節



Souvenir Presentation 致送紀念品

Project WATERMAN Public Lecture Series

3D Environmental Impact Assessment (EIA)

香港近海水質預報及管理系統 — 公開講座系列


3d environmentalimpact assessment(eia)

Documents