Eco-environmental evaluation information system is used to analyze and evaluate the geological and ecological environment of Tuwei River Basin. Based on GIS, the geological ecological environment evaluation is realized.
The integration and visualization of geological ecological environment information storage, management, query, analysis, evaluation and result expression are realized, and the evaluation process and results reflect the land more intuitively.
Spatial distribution of ecological environment and its changing characteristics.
Keywords: GIS；; Geological ecological environment; Evaluation; Tuwei river basin
China Library Classification Number: X820.2 Document Identification Number: Part A Number:1000-1379 (2007) 09-0001-02.
Geological ecological environment assessment involves the extraction, processing, analysis and response of multi-source information.
Use, and the data has spatial properties. The traditional geological ecological environment evaluation is a combination of
After preprocessing the evaluation data, a set of extraction is obtained by using a specific mathematical model.
It is difficult to directly describe the space of geological and ecological environment with the evaluation result data of elephants.
Variability In contrast, GIS plays an important role in the storage and expression of geological ecological environment data.
It has wide applicability. Using GIS technology, by extracting geological ecology
Factors and elements of environmental assessment, combined with professional models for data analysis and evaluation,
It is an evaluation of geological ecological environment to express the analysis and evaluation results in an intuitive graphic way.
One of the effective methods.
Tuwei River Basin is located in Maowusu Sandy Land and Loess Plateau in the east of Ordos Basin.
The original transitional zone, with a total area of 3 294 km. . Affected by special climate, geography and geology.
Limited by conditions, the ecological environment of the basin is fragile. In the energy and heavy chemical industry base and other large-scale workers
In the process of construction, if effective environmental protection measures are not taken, the ecological environment will be destroyed.
Further deterioration leads to new environmental geological problems, which have been quite a few in northern Shaanxi in recent years.
Examples of coal resources and water resources development prove this point. Therefore, the study of this basin
The influencing factors of the emergence and change of quality ecological environment problems, and the environmental assessment under the current conditions.
Environmental conditions, guiding the rational development and utilization of basin resources, geology and ecological environment.
It is of great practical significance to prevent and control this problem.
1 Analysis of influencing factors of geological ecological environment in the study area
1. 1 landform
Topographic conditions control the distribution of groundwater resources and also determine the main
Types of geological ecological environment. The upper reaches of Tuwei River are sandy land, with small topographic relief.
The main geological ecological environment problem is desertification. Because of the thick sand layer and good water permeability,
It is easily replenished by atmospheric precipitation, and the buried depth of groundwater is relatively small, so it presents sandy soil.
Good environment of desert oasis; The lower reaches are loess hilly areas with broken terrain and geological ecology.
The environmental problem is mainly soil erosion, because the terrain is broken, the ditch is deep and steep, and the terrain is undulating.
When it is large, atmospheric precipitation is easy to form surface runoff and loss (the infiltration coefficient of atmospheric precipitation is only
0. 1), the basic conditions for plant growth are poor and the ecological environment is fragile.
1.2 buried depth of groundwater table
The buried depth of groundwater level is the decisive factor of ecological environment type and its spatial distribution.
The change of groundwater depth leads to vegetation degradation and desertification, which is an ecological environment.
The root of deterioration. According to the field investigation, the groundwater table is at different depths.
The impact on surface vegetation is different: when the groundwater level is less than 5 meters, the water
Adequate distribution, good plant growth and good ecological environment; When diving
When the water level is 5 ~ 8 m deep, the water supply is insufficient, and the plant growth is stressed and shallow.
Root plants are not growing well, and deep-rooted plants have withered leaves, which is incompatible with the ecological environment.
Showing a tendency of degeneration; When the depth of the groundwater table continues to increase, most plants are born.
Due to water shortage, reduced vegetation coverage, serious desertification and soil erosion, geological health
The national environment has deteriorated seriously.
1.3 Lithology, structure and water content of vadose zone
Generally speaking, the primary geological and ecological environment is directly related to the lithology of vadose zone.
Connection: on the one hand, the physical properties of topsoil determine its corrosion resistance, watershed
Most areas are covered with sandy soil, and the wind erosion resistance is low, which is not conducive to planting.
The growth of things; On the other hand, the law of water and salt migration in vadose zone directly affects.
With the growth and development of epiphytes, the more homogeneous the lithology and the denser the structure, the more vadose zones there are.
It is beneficial to water and salt migration, but not conducive to water and salt migration. bag
The lithologic change of gas layer and its combination law, the existence of tight lithologic layer, and vertical and vertical cohesive soil.
Upward distribution has great influence on soil water-salt alternation and plant root development. wasteland
Field investigation and indoor analysis show that when there are dense lithologic layers on the section of vadose zone,
The water content and salt content are obviously higher than those of loose rocks, which is beneficial to plant growth.
Provide necessary water and salt.
Soil water content affects plant growth and vegetation succession. Generally speaking,
Within the scope of plant roots, the water content of vadose zone suitable for plant growth is 16% ~
Date of receipt: April 20, 2007
Fund Project: Supported by National Natural Science Foundation of China (40472131); Shanxi(Province)
Supported by National Natural Science Foundation of China (2002D 13).
About the author: Ma Xiongde (1978 I), male, Huzhu, Qinghai, Ph.D., research direction.
Rational development of groundwater and protection of ecological environment.
20%, when the water content is less than the lower limit, plants will die due to physiological water shortage, and the geology is healthy.
The national environment will develop in the direction of deterioration (desertification and soil erosion).
1.4 groundwater quality
Groundwater quality is one of the important signs of environmental quality, and it also affects plant health.
The key factor of the dragon. According to the survey, in the case of a certain depth of groundwater level, with
With the increase of salinity, plants change from aquatic plants to halophytes. In addition, the ground
The chemical types of water affect the growth and development of plants to some extent.
1.5 meteorological and hydrological factors
In the basin, the recharge of groundwater is mainly atmospheric precipitation. Rainfall from June to September
Replenish groundwater in sandy land, beaches and valleys, increase the flow at the bottom of the river and flow to the sky.
However, vegetation has a positive impact; However, in the loess hilly region, slope runoff and confluence are easy to occur.
Leading to the occurrence of natural disasters such as soil erosion. There is basically no precipitation or decline in other months.
Small amount of water, strong evaporation, shallow groundwater, large evaporation and salt accumulation in soil.
The more obvious the effect, the surface vegetation mainly evolved into water-loving and salt-tolerant type.
1.6 Other factors
The factors affecting the quality of geological ecological environment include natural factors and human factors.
In addition to the above factors, natural factors include vegetation types and vegetation distribution, as well as human factors.
Including water resources and mineral resources development, some of which are related to geological and ecological environment.
The correlation of environmental problems is small, and some of them are not suitable for quantification or difficult to predict their changes, so this
This study did not take this into account.
2 Tuhai River Basin Geological and Ecological Environment Assessment
2. 1 evaluation index system and evaluation criteria
Based on the above analysis, the geological and ecological environment quality of Tuwei River Basin was evaluated.
Layer, with geology, hydrogeology, meteorology and hydrology as the standard layer, according to Li
The genus relationship refines each criterion layer into several indexes, and establishes the evaluation of geological ecological environment.
Price hierarchy evaluation index system j. Based on the field survey data, in the reference
According to the grading standards of evaluation indexes at home and abroad, the geological conditions of Tuwei River basin are classified
The environmental conditions are divided into five grades: good, good, medium, poor and poor. See table 1.
Table 1 Classification of Geological and Ecological Environment in Tuwei River Basin
Basic characteristics of classification
There are few ecological and environmental problems, low desertification and salinization, and less groundwater.
Moderate burial depth, excellent water quality, relatively abundant water and high vegetation coverage.
Poke cangue and add cup, there are environmental and ecological problems, but the degree is average, or some kind of geological ecology.
More prominent
Moderate balloon dancing is common and serious, but there is at least one problem.
The ecological and environmental problems in Touhelan left are widespread, one of which is particularly serious and presents a global situation.
The body is developing in the direction of ecological environment deterioration.
There are at least two ecological and environmental problems on the left side, especially the vegetation coverage.
● The problem of desertification or salinization is serious.
2.2 Construction of evaluation platform
In order to realize the unification of evaluation method and computing environment, a method based on.
MAPGIS ecological environment evaluation information system. The system is based on database.
Basic, GIS and database management departments with evaluation model as the core and GIS as the carrier.
The information system integrated with geological ecological environment evaluation model can be used at the same level.
The storage, management, inquiry, analysis, evaluation and summary of geological ecological environment information are carried out on the platform.
Fruit expression, etc.
The system consists of file module and database module. Each module contains
Data management, spatial analysis and data output. In which spatial analysis
(mainly geological ecological environment analysis model) is the core of the system, which is composed of geological ecology
The environmental spatial statistical analysis model and comprehensive evaluation model are composed of two parts. Specific model
Including exponential superposition model, fuzzy comprehensive evaluation model, dynamic clustering model and neural network.
Network model, etc.
2.3 Geological ecological environment evaluation
Considering the difference of eco-environmental conditions under different landform conditions, combined with actual evaluation
Tuwei River Basin is divided into 500 evaluation areas with a length of 2.5 km×2.5 km.
Unit, evaluate the ecological environment quality, and the evaluation method adopts fuzzy comprehensive evaluation method.
Method, the weight is given by analytic hierarchy process.
The evaluation results are consistent with the existing research results and field survey results, which basically reflect
Introduction to the ecological environment of Tuwei River Basin (Figure 1): Under the current conditions, sand dunes have been cleared.
Outside the mausoleum area, the ecological environment of the basin is good; Although the present situation of ecological environment in desert areas
Yes, but once disturbed by human activities, it will deteriorate rapidly, so it will cover the sand mountain.
Area and desert area are the focus of ecological environment protection in the basin.
3 Conclusion
Figure 1 evaluation results
(1) A geological and ecological environment evaluation information system based on MAPGIS is established.
The system has laid a foundation for the informatization and standardization of geological ecological environment data.
(2) Through the investigation of the geological and ecological environment of Tuwei River Basin, the geological ecology of this basin was revealed.
Environmental factors, put forward the classification standard of geological ecological environment.
(3) Using the established system, the geological and ecological environment quality of Tuwei River Basin was evaluated.
The evaluation results are consistent with the actual situation.
(4) Geological ecological environment evaluation based on GIS realizes the visualization of geological environment.
It integrates the storage, management, query, analysis, evaluation and result expression of environmental information.
Visualization improves the scientific management and comprehensive analysis ability of geological ecological environment data (continued from page 5) (continued from page 2), and the evaluation process and results are more intuitive.
It reflects the spatial distribution law and changing characteristics of geological ecological environment quality.
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Set up 4 stations, evenly distributed on the left and right banks of the main stream of the Yellow River; The old course of the Yellow River is wet.
Two stations can be established in this area. ② The layout of groundwater quality monitoring stations should be as close to the ground as possible.
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5 conclusion
The research on environmental monitoring method of Yellow River estuary wetland based on water cycle is to develop wetland.
The foundation of environmental research is also an important part of the Yellow River ecological environment monitoring, which is even more important.
It is the basis for scientifically formulating the protection and utilization countermeasures of the Yellow River 1: 3 wetland. Carry out this work
Maintain the ecological balance of the Yellow River, protect the biodiversity of the Yellow River 1: 3 wetland, and promote
The sustainable development of the Yellow River 1: 3 wetland has maintained the local and surrounding ecosystems.
Health and safety are very important. Therefore, a complete Yellow River 1: 3 wet system should be established as soon as possible.
Earth environmental monitoring system.
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