Watershed classification in Taizi River 孔维静 Chinese Research Academy of Environmental Sciences
Watershed classification in Taizi
River
孔维静
Chinese Research Academy of
Environmental Sciences
Outline
• 1. Natural, geographical and freshwater
ecosystem features in Taizi river watershed
• 2. Why classification
• 3. Method
• 4. Results
1.1Overview
40° 29′ -41°40′N
122 ° 25 ′-124 ° 55 ′E
Temperate continental monsoon climate
Area: 12,000KM2
Province: Liaoning
DEM Geomorphology Soil type
Annual average temperature Annual average rainfall Vegetation
1.2 Environment variables for Taizi river watershed
Environment
variables Rationale
Temperature Determines the spatial pattern of species distribution
Precipitation
Related to watershed water cycle and water resource distribution,
determining species distribution, ecosystem process and dynamics
DEM Related to temperature, rainfall and hydrology, influencing species
distribution, freshwater ecosystem type, spatial pattern and ecosystem
process
Soil Related to water cycle, influencing hydrological process, biogeochemical
process and freshwater ecosystem structure and function
Vegetation Offering habitat for freshwater organisms, related to water temperature
adjustment, sunlight penetration, soil erosion and biogeochemical process;
influencing freshwater ecosystem structure and function
Slope Related to regional or local macro-habitat, influencing freshwater structure
and function
1.3 Environmental variables and its ecological importance
Environmental variables influence freshwater ecosystem
1.4 Freshwater ecosystem: Macroinvertebrate community structure
Individuals Dominant species Species
Individuals, species and dominant species for macroinvertebrate are different
among Taizi river watershed
1.5 Freshwater ecosystem: Fish community structure
Individuals Species
Dominant Species
Individuals, species and
dominant species for fishes are
different among Taizi river
watershed
1.6 Freshwater ecosystem: Alage community structure
Individuals Species
Individuals and species for algae are different among Taizi river watershed
1.7 Results
• Environmental variables changes from the upper Taizi river to
lower Taizi river
• Freshwater community structure changes from the upper Taizi
river to lower Taizi river
2. Why classification
• Spatial heterogeneity of environmental variables
• Spatial heterogeneity of freshwater ecosystem
structure
• Base for river health assessment
• Management demands
3. Method---classification scheme
Data source:DEM,slope,aspect, vegetation type,soil type,annual average
temperature,annual rainfall,annual evaporation;NDVI
Qualitative
analysis of spatial
distribution pattern
Geostatistic
analysis
Correlation Analysis between
aquatic organisms and
environmental variables
Environmental Indices chosen for the classification
unsupervised classification results
Final classification map
Small catchments boundary Modify with aquatic
organisms cluster map
aquatic
organisms
survey data
Aquatic
organisms
cluster map
cluster
ISODATA
4.1 Results
Relationship between freshwater organisms and environmental factors
Environmental variables influences freshwater ecosystem structure, so its
pattern can be used to reflect the freshwater ecosystem pattern in Taizi river
watershed
4.2 Results
DEM slope Annual
Evaporation
Annual
Temperature
Annual
Precipitation
NDVI
Range 101.28 KM 84.43 KM 132.1 KM 87.28 KM 100.3 KM 92.37 KM
Spatial autocorrelation range calculated from geostatistic
DEM and precipitation were suitable for the classification
DEM Annual average rainfall
Database
4.3 Results
ISODATA unsupervised classification results in ERDAS
4.4 Results
Check with freshwater organisms and boundary revision
Classification by
natural attributes Small watershed
boundary
Ⅰ Mountainous forest region
Ⅱ Hill forest region
Ⅲ Plain agriculture region
Freshwater
organisms
pattern
Region Watershed features River feature Freshwater ecosystem
Mountainous
forest
region
Area: 4557KM2,
Mean DEM: 511m;
Annual average temperature:
2.28-7.75;
Annual average precipitation:
786-954mm
Mean river width 14.79 m (0.5-100m);
Mean substrate index: 3.6 (1-4.8);Mean
suspended solid: 33.7mg/L (3.5~
347mg/L);Mean DO: 10.8 mg/L (4.3~
15.6 mg/L); Mean conductivity: 183μs/cm
(11.7~826μs/cm)
Dominant fishes: Leuciscus waleckii、
Cottus pollux, Odontobutis obscurus;
Dominant macroinvertebrate:
Ecdyonurus viridis, Paraleptophlebia
japonica;Above ground herbaceous
biomass: 1.04kg/m2,belowground:
0.55 kg/m2,Total: 1.68 kg/m2
4.5 Ⅰ Mountainous forest region
Region Watershed features River features Freshwater ecosystem
Hill
forest
region
Area: 3896KM2;
Mean DEM: 282m;
Mean annual temperature: 6.9℃
(4.38-9.22℃);
Mean annual average precipitation:
784mm(717-868mm)
Mean river width: 44.4m (0.3-300m);
Mean substrate index: 3.4(1-4.4);
Mean suspended solid: 30.3 mg/L(5.5~
81.5 mg/L) ;
Mean DO: 9.4mg/L (3.5~14.6 mg/L);
Mean conductivity: 336.8μs/cm (57~
566μs/cm)
Dominant fishes: Ctenogobius brunneus,
Hemicculter Leuciclus,
Squalidus chankaensis;
Dominant macroinvertebrate:
Cheumatopsyche sp., Antocha sp., and
Beatis thermicus;
Above ground herbaceous biomass:
1.25kg/m2,belowground: 0.72 kg/m2,
Total: 1.97 kg/m2
4.6 Ⅱ Hill forest region
Regions Watershed features River features Freshwater ecosystem
Plain
agriculture
region
Area: 4749KM2;
Mean DEM: 65m;
Mean annual temperature:
8.6℃(4.9-10℃);
mean annual precipitation:
708.8 mm (653.6-775.1mm)
Mean river width: 84m(1-400m);
Mean substrate index: 2.1(1-4.2);
Mean suspended solid: 32.3
mg/L(3.5~109 mg/L);
Mean DO: 6.4 mg/L(0.4-13mg/L);
Mean conductivity: 515μs/cm(177~
1126μs/cm)
Almost no fish, occasional
species Ctenogobiusgiurinus;
Above ground herbaceous
biomass: 1.51kg/m2,
belowground: 0.93 kg/m2,
Total: 2.45 kg/m2
4.7 Ⅲ Plain agriculture region
Thanks for your attention!