Dec 16.1 11.6 13.6
Pre-Tang/Shenwo
Post-Tang/Shenwo 10.3 Post-Guanyinge 12.6
Cease to flow
Liaoyang
350
Days of cease to flow
Cumulative annual days of cease to f low
– – – – Velocity Depth Width Shear stress hydraulics
Flow components
King et al (2008) Building Block Method
Baseflows
Benxi
45
Median baseflow daily discharge (m3/s)
Benxi
18/06/2001 24/05/1978
120
Elevation (m ASL)
115 110 105
100
0 50 100 150 200 250 300 350
• Ostensibly 表面上 :
– “ecologically meaningful” “生态意义”
• Warning 警告
– From a different area 从一个不同的区域 – Not linked to ecological assets of interest 没有联系到当地的生态环境
Objectives 目标
• Assess hydrological health of Taizi River
• Try an index of hydrological stress • Develop a new method sensitive to:
– – – – Local ecological assets Local hydrology Local flow-ecology knowledge Closely linked to flow management options
Hydrological change Index value
1.0
0.9 0.8 0.7 0.6 0.5 0.4 0.74 0.991 0.92
1.0
0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.06 0.09 0.32 0.00 0.68 0.77 0.84 0.912
Dec 5.6
13.9
Pre-Guanyinge Dam
Post-Guanyinge Dam 14.2
Baseflows
70
Tangmazai
Median baseflow daily discharge (m3/s)
60 50 40 30 20 10 0
Jan 9.3
Feb 8.6 10.0 13.3
Median and Interquartile range [exceeded 75 - 25 percent of time]
Jan Feb Mar Apr May Jun 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0
Jul
Hale Waihona Puke Aug Sep Oct Nov Dec 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0
Yingkou
Flow data from 1950s
Daily discharge (m3 /s)
Daily discharge (m3 /s)
2,000
1,500
Flow exceeded 5 percent of the time
Benxi
2,500 2,000 1,500 1,000 500 0
Catchment management policy
Physical Geology Climate Land use Hydraulic habitat
Economy Education Trade, etc
Hydrology
Geomorphology
Ecological river health
Flow exceeded 5 percent of the time
Tangmazai
1,000
500
0 Jan Feb Mar Apr May Jun 350 300 250 200 150 100 50 0 Jul Aug Sep Oct Nov Dec
Jan Feb Mar Apr May Jun
Liaoyang (pre-Tanghe/Shenwo V. post-Tanghe/Shenwo)
Hydrological change Index value
1.0
1.0
0.9 0.8 0.7 0.6 0.5 0.4 0.60 0.60 0.77 0.87 0.73 0.55 0.59 0.980
Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
Relative interquartile range [IQ range/median]
Relative interquartile range [IQ range/median]
Relative IQ range
0.79
0.78
0.67
0.62
0.64
0.54
0.44
0.54
0.3
0.2 0.1
0.34 0.13 0.03
0.0
Xiaolinzi (pre-Tanghe/Shenwo V. post-Guanyinge)
Hydrological change Index value
1.0
0.9 0.8 0.7 0.6 0.5 0.4 0.66 0.58 0.65 0.48 0.34 0.10 0.03 0.86 0.90 0.937
• Is it OK to mix response and driver variables? • YES
• Hydrology is open to management action to improve health
Choices 选择
• Indicators of 指标 :
– – – – – Hydrological Hydrological Hydrological Hydrological ……. alteration stress disturbance deviation
Benxi (pre-Guanyinge V. post-Guanyinge)
Hydrological change Index value
0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.10 0.18 0.35 0.59 0.47 0.683 0.99 0.85
Jul Aug Sep Oct Nov Dec
Median and Interquartile range [exceeded 75 - 25 percent of time]
Daily discharge (m3 /s)
Daily discharge (m3 /s)
1,000 800 600 400 200 0
Can measure differences in periods Does not work on a single year
0.46
0.3
0.2 0.1
0.0
Rapid eco-hydraulic environmental flows assessment
• We need to know about the eco-hydraulics • What specific flows will satisfy the needs of the identified ecological assets? • Ecology responds to
River management policy
Social river health
Water quality Chemical
Ecological processes Biological
Main Issues 主要问题
• Hydrology RESPONDS to catchment and disturbance • Hydrology DRIVES the ecology
Annual peak cease to f low spell duration
300
250 200
150 100 50
0
Tangehe Shenwo
Guanyinge
Flow events
Frequency
Duration
Hydraulic information
• • • • No surveys Need to find whatever is available Gauging stations have useful information Can derive as a function of discharge:
– – – – Velocity Depth Width Shear stress
• These variables are used to determine the discharge that will satisfy the hydraulically defined ecological and geomorphological objectives
40 35 30 25 20 15 10 5 0 Jan 3.7 Feb 3.8
15.1
Mar 4.0