2016 International Conference on Environment, Climate Change and Sustainable Development (ECCSD 2016) ISBN: 978-1-60595-358-8

A Study on the Water Environmental Impaction Mechanism of Huaxi Wetland Park in the Process of Urbanization

Ting SUN 1, Fei-yan DENG 1, Shu-lin JIAO 1* and Dong-wei CHEN 2 1School of Geography and Environmental Science, Normal University, 550001, 2Guiyang Engineering Corporation Limited, Guiyang, Guizhou 550081, China *Corresponding author

Keywords: Urbanization, River water environment, Runoff, Huaxi urban wetland.

Abstract. In order to investigate the impact mechanism of urbanization on waters, Huaxi environment, the analysis was carried out on the watershed forest cover, precipitation, stream water quality, wastewater discharge and treatment, such as river pollution investigation on the influencing factors of water environment. As a result, the influence mechanism and its protection counter measures of water environmental problems were drawn up. Urban development led to a series of soil and water environmental problems on the great pressure of urban water environment in the process of urbanization, due to the fragility of its environment in karsts area, especially in Huaxi. With the urban land expansion of Huaxi country, it was increasing of new immigration residents that mainly varied impact degrees of the wetland water environment.

Introduction Being one of the most productive and the most valuable ecosystems in the world as one of the most widespread distribution landscape types, the wetland is an important significance in the world, in which wetland has its own features make it become a lot of leisure, tourism, health, entertainment place and so on. The wetland is well known as "kidney of the earth" for the enormous ecological environmental benefits and function of adjust microclimate, water conservation, etc. Huaxi wetland park, as a major source of Huaxihe river, is facing serious water environment challenges under the impetus of the economic development and urbanization. As urbanization speeding up of Huaxi country, the area of the destruction of environment, increased urban pollution sources, waste water infiltration, the change of water flow and water pollution. Therefore, this study based on the influence factors of Huaxi wetland park water environment change, discussed karst area urbanization impact on water environment change mechanism, in karst area defense strategy is put forward. Huaxi national wetland park, being in the center of the city of Huaxi as a south center of Guiyang city, locates in 106.5 degrees east longitude, 26.18 degrees north latitude ranged Shilihe river flooded plate ,Huaxi district park, as well as sightseeing agricultural belt from Luopingcun to PingQiaocun village with 1140 meters in an average elevation. Huaxi wetland park is located in China's southwest karsts of landforms developed and humid monsoon climate zone being usually under the influence of the southeast and southwest monsoon and the impact of Kunming quasi-stationary front in which the karst landform developed widespread with a series of the karstification, crack, funnel, dissolving tunnel, dissolve gap, frequent water exchange between surface water and groundwater because of the widely distributed limestone and large rocks exposed area in the condition of the abundant precipitation and higher humidity. Guiyang Huaxi national wetland park was approved to build by the ministry of housing and urban-rural in December 2009, which is the first national urban wetland park covered an area of 460 hectares of southwest China. Huaxi national wetland park district includes over 50 streams draining about 20.5 km 2 belong to the Yangtze river water system in the Huaxi district where the exposed rocks are limestone, dolomite, quartz sandstone, siltstone and nacreous shale (Huaxi) which was

developed respectively in the periods of Devonian, Carboniferous, Permian and Triassic, Jurassic, Quaternary. The geological structure and modern landscape effect form terrain characteristics of anticline mountains, syncline into valley. In recent years, because of university town of Guizhou province in the DangWucun village was built and put into use gradually, the urbanization process was accelerated largely making the local economy rapid develop and nonnative personnel increase as well as regional infrastructure improve. By the end of 2010, Huaxi county area has total population 0.360054 million including urban population 0.157393 million and agricultural population 0.202661 million with 43.71% urbanization ratio. In 2010, there are population size of 58000 in Huaxi main urban area, including non-agricultural population of 43000, the agricultural population of 7000 as well as the floating population of 8000. City area amounts to 9.18 square kilometers, of which the urban construction land area of 4.226 square kilometers. During the "13th five-year plan", Huaxi district have elaborately created the six industrial park,such as Xiaomeng eco-industrial park, Jinshi Stone industrial park, Qianfeng biological science and technology park, Yanlou circular economy industrial park, Huaxi university town high-tech business incubator and the Yangai agricultural products processing base.

Research Method In this study, we establish a database getting through the study of the changes of the stream flow in different periods including the change of forest cover area, the change of precipitation, the rate of urbanization as well as the water quality environment of the Huaxi river. We use the buoy method to measure the flow measurement and use the related literature to record and analyze their correlation.

Results and Discussions

Regional Present Situation of Soil, Vegetation and Hydrological Characteristics Huaxi District Soil, being impacted by geological and climate conditions, are mainly covered acidic yellow soil, followed by yellow limestone soil, purple soil, paddy soil, fluvo aquic soil and so on. Huaxi national urban wetland park is in Huaxi Zhongcaosi trough valley of Guiyang syncline rightside, in which the outcroppings of main stratum and lithology is the bottom Triassic system group Zhongyuan layer lower segment and thin layer of dolomite and dolomitic limestone. Huaxi Karst landform almost is Peak cluster trough and peak-cluster basin. At present, the soil pH value of Huaxi Wetland Park is 5.3 ~ 6.2. According to the soil and radioactivity field measurement data of Bureau of Geology and Mineral Resources in Guizhou province (now is Guizhou province Geological and Mineral Exploration and Development Bureau) in Guiyang region, we know the soil pollution element content such as mercury, arsenic, aluminum respectively are 200 ~ 400ppm, 100 ~ 200ppb, 10ppm, 25 ~ 45ppm, are not appear to exceed the normal level. The region's land area is 957.6 square kilometers in which there are 11849 hectares arable land area is and 309.88 km 2 forest area in coverage ratio 32.36%. This area is in subtropical evergreen broad-leaved forest vegetation zone, but the original vegetation has ceased to exist in addition to the remaining part of evergreen broad-leaved, such as Photinia davidsoniae and Cinnamomum bodinieri species etc.. There are six main types of natural vegetation such as coniferous forest, coniferous and deciduous mixed forest, deciduous forest, sparse forest, shrub grass and grass slope. Artificial vegetation coverage rate is 26.07% which is mainly including Chinese fir forest, pine forest, as well as economic forest with tea tree as the main body and some pasture. Cultivation and existing in the wild plants which is over 120 families, 1000 species and variants, with sweet fruit trees, hemlock, Keteleeria, Liriodendron, Cyclocarya paliurus, Cephalotaxus fortunei, ginkgo, beech, ledong intends Kmeria septentrionalis and water Highline flowers of rare tree species. The float method is used to measure the flow volume of a floating body in a fixed reach river, and then to measure the time used by the floating debris through fixed reach river. Using methods of stream segment volume divided by the using of the time we can get the river velocity of stream segment. Formula: Q=V/t, in which Q means flow, V means stream segment water volume as well as t stands for time (all the other years data are from Huaxi Environmental Protection Bureau except field measurement data in 2013 and 2014). Table 1. The average flow rate in different periods of Huaxi Wetland Park (2007—2014)(m 3/s). Time 2007 2008 2009 2010 2011 2012 2013 2014 Wet season 5.41 5.95 5.23 5.57 5.61 5.80 6.01 5.97 Dry season 3.10 3.21 3.42 3.01 3.24 3.51 3.61 3.47

We found in the survey that the wet season average runoff of the river in Huaxi during the period from 2007 to 2010 was 5.53m 3/s and the dry season average runoff was 3.24m 3/s, while from 2010 to 2014 the wet period average runoff reached 5.79m 3/s and the dry season was 3.49m 3/s. The mean flow of two time interval in wet season and dry season is 0.26m 3/s and 0.07m 3/s respectively, while the highest flow difference of wet season and dry season was 0.78m 3/s and 0.81m 3/s respectively. The Meteorological Elements Change of Different Stages of Research Area According to the changes of different stages meteorological factors in the Huaxi River of Huaxi national wetland park, we studied the change of the regional meteorological elements in the period of precipitation, humidity, sunshine time, as well as the temperature. As the main source of water supply in Huaxi river is from the atmospheric precipitation, the change of sunshine duration and temperature in the river basin is an important influence on the evaporation of the regional water environment which even plays a decisive role. And the increasingly accelerated urbanization process will have a certain impact on the region's meteorological elements, such as the urban heat island effect. So it is a significance for the regional water environment that to study the changes of meteorological factors in the Huaxi River region. (data come from the library of the school of geography and environmental science, Guizhou Normal University, Guizhou). Table 2. Monthly average temperature of mean (T), maximum (Max.T) and minimum (Min.T) respectively in Huaxi National Wetland Park between the interval 1964~2009 and 2009~2014(°C ). Month 1 2 3 4 5 6 7 8 9 10 11 12 1964 T 4.8 6.8 10.8 15.6 19.3 21.8 23.1 22.8 20.2 15.9 11.6 6.6 ~200 Max.T 8.7 10.4 15.9 20.4 23.7 25.9 27.3 27.6 24.7 20.4 15.4 11.3 9 Min.T 2.3 3.6 7.2 12 15.6 18.7 20.1 19.4 16.3 12.6 8.1 3.4 2009 T 4.9 6.4 10.2 15.1 20.3 22.0 23.7 22.5 19.4 15.3 10.7 6.9 ~201 Max.T 8.4 9.9 15.9 20.8 24.1 26.5 27.5 27.7 25.1 20.0 15.1 11.0 4 Min.T 2.1 3.5 6.7 12.3 15.8 18.9 21.0 20.1 16.9 11.6 7.8 3.5 Table 3. Monthly average volume of Precipitation (P), Relative humidity (Rh) and Sunshine time St) respectively in Huaxi National Wetland Park between the interval 1964~2009 and 2009~2014. Month 1 2 3 4 5 6 7 8 9 10 11 12 1964 P/mm 23.8 24.6 36.8 86.9 165.3 231. 183.3 119.9 111.0 92.6 45.4 17.8 ~200 1 9 Rh/% 83.0 81.0 78.0 79.0 81.0 82.0 84.0 84.0 82.0 83.0 82.0 80.0 St/h 43.7 51.2 85.2 109.2 121.9 111.4 165.2 174. 121. 96.9 75.3 68.2 1 6 2009 P/mm 23.7 24.9 36.5 89.7 167.0 239. 186.3 123. 109. 94.6 45.0 18.2 ~201 1 4 0 4 Rh/% 82.0 82.0 79.0 80.0 82.0 83.0 84.0 84.0 82.0 83.0 82.0 81.0 St/h 42.8 9.7 85.2 109.0 122.3 110. 163.9 171. 122. 97.7 75.0 65.1 5 9 6 The urbanization process of Huaxi district Guizhou province should be divided into two stages to comparative study taking the 2010 as the dividing line, because the quickly urbanization process of the Huaxi district happened largely after 2010,after when the level of urbanization reached 43.71% in 2011, the urbanization rate come to 44% during the Eleventh Five-Year Plan period, and the

urbanization rate of Huaxi district reached 75% during the Twelfth Five-Year Plan period, the total population have reached 5.5*10 5 people. According to meteorological elements of Huaxi area, through comparing the 1964-2009 and 2009-2014, it can show us that their every month average temperature, the average maximum temperature, the average minimum temperature have the relative small change amount of this two interval in which the average discrepancy was 0.15, 0.025 and 0.45 degrees Celsius respectively. The average relative changes of every month average rainfall, relative humidity, sunshine time are +1.575mm, +0.417%, -0.067 hours respectively. In this change data, the average monthly rainfall and relative humidity have increased, while the sunshine number has decreased because of the urbanization effects. Analysis of River Water Quality Data in Huaxi Wetland Park Water quality in water environment of the area are mainly affected by the influence of the amount of metal ion is contained in rivers, the level of water quality is mainly partition by the toxic metal ions, dissolved oxygen, chemical oxygen demand (cod), total nitrogen, total phosphorus, ammonia nitrogen content of water. In order to study the metal content in the area, the two sampling methods are mainly adopted. The first one is that to sampling in the upstream, middle reaches and lower reaches of the river, and the second is to sampling in the mainly pollution point of the river. The study found that the pH is between 7.7 to 8.3 in the area, which belongs to the weak alkaline water. The temperature change of the water body in the Huaxi river is between 13 to 24 degree centigrade the whole year, and the changed of water temperature is so bigger(data is from Huaxi Environmental Protection Bureau). According to the scope of the natural environmental change, the impact of water quantity in the Huaxi river can be ignore. So as we known that the change reason of the Huaxi river water quantity(Table 4) a large extent is the human factors. Table 4. Water quality parameters and its relating index of Huaxi Wetland Park. Metal ion As (ug/L) Hg (ug/L) Pb (ug/L) Cd (ug/L) Cr (ug/L) Concentration range 0.078~0.195 0.002~0.00578 0.142~0.562 0.0067~0.014 0 Class I water quality 0.05 0.00005 0.01 0.001 0.01 standard ≤mg/L Park drainage 1.25 0.017 1.93 0.20 0 Guizhou Nationalities 0.46 0.01 0 0.12 0 University Sanitary sewage 1.15 0.006 4.78 0.19 0 Zhongcaosi 9.34 0.41 2.4 0.26 0.12 Table 5. Dissolved oxygen, chemical oxygen demand, total nitrogen, total phosphorus, ammonia nitrogen content in different water samples in Huaxi Wetland Park(mg/L).

Index DO COD TN TP NH 3-N Range(mg/L) 0.35~6.9 1.48~5.67 1.51~5.78 0.05~5.87 0.83~3.81

In the Huaxi district, the domestic water consumption standard is 100L/(p·d),and the water consumption standard of public facilities is 2000 m3/(km 2·d).The water consumption standards for land use in production facilities is 10000 m3/(km 2·d),the water consumption standard of other sites (including sites of warehousing, road square, municipal facilities, landscaping etc.)is 1.5000 m3/(km 2·d). Pipeline leakage and unforeseen water consumption accounts for 20% of the total amount of water consumption in above (huaxi city planning). According to the analysis of the data that collected from the different reaches of the river in the Huaxi River Wetland Park, it is notable that the content of toxic metal elements in the river is lower than those of the indexes of the national standards. Referencing to National Surface Water Quality Standard, we can know that the water quality of the Huaxi river is mainly belongs to the class II water quality and Class III water quality. The metal ion concentration of main polution drainage point is higher than those of the indexes of the national standards belonging to the class IV water quality. Along the river side of the Huaxi River is mainly urban commercial land and residential land, Huaxi River Wetland Park Shilihetan flood plain area has a lot of farmland. Among this that the agricultural water is mainly from the river, in which the agricultural fertilization and pesticides have an important influence on the water quality of the area. The amount of fertilizer and pesticide we used in Huaxi district were 536kg/hm 2 and 8.24kg/hm 2 respectively which exceed 52% of the national average level. A large part of residents and commercial housing domestic water are large number of directly into the river without treatment, which are the main sources of population of the river. From the river runoff changes as you can see, the flow of Huaxi river are all increased in the dry season and the wet season since 2010 with the rate of change of wet season having a large change. It is mainly reason for the increasing discharge with the urbanization process that the urban sewage discharge are increased and the urban road hardening in the urbanization are generalization, so the precipitation in the road of the wet season flow into the underground passage then influx the Huaxi river. The change of content of NH 3-N, COD, TP, TN and DO in the Huaxi River are mainly due to the influence of river runoff effect ,wastewater discharge as well as the large amount of aquatic plants having not been cleaned effectively in the river. It is the large number of plant bodies decomposed in the river that caused the TP, NH 3-N, TN NH 3-N to increase sharply. As a result, the dissolved oxygen in the water decreased for the decomposed quatic plants consuming a large amount of oxygen.

Conclusion First of all, the flow change of Huaxi Wetland Park river basin is not because change of climate factors, which is mainly caused by the water consumption and the drainage of the road during the process of urbanization. Secondly, the a large part of reason is the pollutants in the production life of cities, which made the DO and COD, TN, TP, NH 3-N and its heavy metal content of the river increase obviously. There are also some natural causes of a large number of aquatic plants growing in the river in which a large number of decomposed plant bodies make the contents of DO decrease, and the contents of NH 3-N, TP, TN and COD increase in the riverine water. Thirdly, in the Huaxi river one side and Shili beachland scenic area, there has pollution drainage of part the housing construction has the serious influence to the river, especially a stretch of river beside because a large amount of sewage discharging into river makes COD, TN, TP, NH 3 -N content increase.

Acknowledgement This research was financially supported by Guizhou province science and technology fund (Qiankehe J [2012]7005, Qiankehe J [2013] 300&2290&2298) and the national natural science fund (41263011).

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