Has Suspended Sediment Concentration Near the Mouth bar of the Yangtze estuary been decling
https://www.wendangku.net/doc/198911194.html,
Has Suspended Sediment Concentration Near the Mouth Bar of the Yangtze (Changjiang)Estuary Been Declining in Recent Years?
Zhi-Jun Dai {*,Ao Chu {*,Wei-Hua Li 1,Jiu-Fa Li {,and Hua-Lin Wu 1
{
State Key Lab of Estuarine &Coastal Research East China Normal University Shanghai 200062,China zjdai@https://www.wendangku.net/doc/198911194.html,
{
College of Ocean Hohai University 1Xikang Road
Nanjing 210098,China ao_chu@https://www.wendangku.net/doc/198911194.html,
1
Key Lab of Estuarine and Coastal Research Ministry of Transport Shanghai 201201,
China
ABSTRACT
Dai,Z.-J.;Chu,A.;Li,W.-H.;Li,J.-F.,and Wu,H.L.,2013.Has suspended sediment concentration near the mouth bar of the Yangtze (Changjiang)Estuary been declining in recent years?Journal of Coastal Research,29(4),809–818.Coconut Creek (Florida),ISSN 0749-0208.
There are considerable concerns about the decrease in suspended sediment discharge (SSD)into the large estuaries of the world as a result of extensive anthropogenic activities in their catchment areas.With the operation of Three Gorges Dam (TGD)in 2003,the riverine loads into the Yangtze (Changjiang)Estuary have been greatly changed with the sharp decrease of SSD and suspended sediment concentration (SSC).However,according to our analysis on the SSC in the surfacial water measured at different stations in the Yangtze Estuary,we conclude that the spatial characteristics of the annual mean SSC around the mouth bar area show no apparent change yet,even though the TGD was constructed with an ascending trend at the upper part of the estuary.The spring–neap periodicity of the daily mean SSC after the TGD was constructed remained the same as before.Moreover,the seasonal and annual mean SSC at the inner side of the mouth bar was relatively low due to the large reduction of upstream sediment supply after the operation of TGD began in 2003.But the seasonal and yearly mean SSC at the outer side of the mouth bar during 2007–2009is comparable with those before the TGD operated,even though there is a decreasing trend of SSC into the Yangtze Estuary in corresponding years.
ADDITIONAL INDEX WORDS:Suspended load,suspended sediment concentration,dams,anthropogenic action,the
Yangtze Estuary.
INTRODUCTION
Estuaries are commonly defined as places where tidal action mixes waters from the sea and rivers (Dyer,1997).Estuaries have a special role in sustaining flora and fauna,navigation and recreation,and shore-based industrial and residential development (Prandle,Lane,and Manning,2005).Because of the large reduction in the suspended sediment discharge (SSD)of most estuaries in recent decades,great changes in estuarine environments have taken place including coastal retreat,changes in the benthic environments of estuaries,and vanishing coral reefs (Milliman,1997;Syvitski et al.,2005).However,because of complex factors controlling variations in river sediment loads,such as topographic gradient,basin size,and human interference,SSD changes in upper streams are sometimes not directly reflected in lower river reaches (Brizga and Finlayson,1994;Chakrapani,2005;Phillips,Slattery,and Musselman,2004;Shi,Zhang,and You,2003).In addition,the sediment output or accumulation in some rivers has been remarkably consistent,despite changes in climate,sea level,
vegetation,and human impacts (Dearing and Jones,2003;Gunnell,1998;Phillips,2003Summerfield and Hulton,1994).For example,no dam-related changes in alluvial sedimentation are noticeable in the lower river reaches of southeast Texas,although large reservoirs control 75–95%of the drainage area,and retain massive amounts of water behind dams (Phillips,2003;Phillips,Slattery,and Musselman,2004).A key question is therefore:how does the changing SSD upstream affect suspended sediment distribution in estuaries?This has received extensive attention in estuarine environments (Eisma,1993;Phillips and Slattery,2006;Syvitski et al.,2005;Walling,2006;Walling and Fang,2003).
Recent trends in SSD into estuaries in most large rivers have been discussed by Walling and Fang (2003).Main focus has been placed on the decrease of SSD in estuaries resulting from dams (Syvitski et al.,2005;Walling and Fang,2003;Xu and Milliman,2009;Yang et al.,2005;2007).However,Phillips and Slattery (2006)pointed out that most of the previous studies on the changes of SSD being carried into estuaries were mainly based on measurements near the tidal limits of estuaries,where the SSD may not directly represent the SSD brought into the estuaries.The distance from the tidal limit to the estuary mouth can be a long buffer,sufficient for the SSD to change from the upstream value into the estuarine value.On the other hand,because SSD and discharge are partly trapped
DOI:10.2112/JCOASTRES-D-11-00200.1received 8November 2011;accepted in revision 17December 2011.*Corresponding authors.
’Coastal Education &Research Foundation 2013
Journal of Coastal Research 294809–818Coconut Creek,Florida July 2013
behind upstream dams,the amount of marine sediment can be increased in the estuary by relatively strong tidal currents, resulting in changes in the SSD in estuaries(Phillips and Slattery,2006).Therefore,the variation of suspended sediment in the estuary results from the combined influences of upstream changes and the reaction in the estuary.The area around the mouth bar of an estuary is the main site of the interaction between marine and fluvial forces.It is important to study the SSC characteristics near the mouth bar to gain knowledge about morphodynamic processes within the estuary. The Yangtze River,the largest river in China,is a special example of the above situation.Because of intense human activities in the Yangtze River basin,including vegetation destruction,deforestation,and dam construction,the SSD in the Yangtze Estuary has changed(Dai et al.,2011a,b;Liu et al., 2007;Xu et al.,2006;Yang et al.,2005–2007).It has been reported that the annual SSD entering the Yangtze Estuary has significantly decreased since the late1960s,as the annual mean SSD in the1990s of3433106t,accounting for two-thirds of that in the1960s(5003106t)(Yang et al.,2004). Subsequently,since the world’s largest hydroelectric dam,the Three Gorges Dam(TGD),started trapping water in2003,the SSD at Datong,the tidal limit of the Yangtze Estuary about 640km from the mouth,decreased to206,147,and2163106t in2003,2004,and2005,respectively.In2006,the historical lowest annual SSD and the annual mean SSC at Datong in last half century,were recorded as853106t and0.123kg/m3, respectively.As a result of the large sediment reduction upstream after the first impounding phase of the TGD in 2003,the sediment supply into the Yangtze Estuary has significantly decreased.However,until now,SSC change in the Yangtze Estuary or around the mouth bar area in the estuary had not been reported after the TGD construction.Thus,on the basis of our analyses of the SSC measurement near the mouth bar in the Yangtze Estuary and at Datong before and after the TGD construction,this paper presents the nature of the SSC near the mouth bar area in the past two decades and the associated controlled factors are also addressed.
MATERIALS AND METHODS
The SSC data were collected at various stations,shown in Figure1and Table1.Xuliujing and Hengsha are located around the bifurcation points for the North/South Branches and the North/South Channels,respectively.Hengsha is also located at the inner side of the mouth bar and is a representative of the inner side of the mouth bar,whereas the data at Xuliujing represent the upper part of the Yangtze Estuary.Sheshan,Niupijiao,and Nancaodong are located at the mouths of the North Channel,the North Passage,and the South Passage of the Yangtze Estuary,respectively.The water samples at Xuliujing,Hengsha,and Shenshan were collected at 1m below water surface at0800and1400every day from January1999to December2000with500-ml bottles.The suspended sediment concentration(SSC)was analyzed in the laboratory(Chen et al.,2006)and the mean value of two SSC values from the same day is regarded as the daily mean.The data at Niupijiao,Nancaodong,and Hengsha in2006were measured hourly by Optical BackScatter Sensor(OBS)instru-ments at the same water depth and calibrated against discrete water samples with the method of Buchanan and Ruhl(2000) (Table1).The mean value of SSC at each hour of the same day is used to represent the daily mean value.In addition,the monthly mean data at Niupijiao,Nancaodong,and Hengsha during2007–2009from hourly OBS observations were avail-able from the Science Centre of Estuarine and Coastal Research of Shanghai(Table1).Moreover,because of the occasional instrument fault or typhoon/storm passing over this region,the lost data were obtained by interpolated analysis. Frequency statistical analysis and spectrum analysis of the SSC data were applied to study the characteristics of the SSC. Frequency statistical analysis was useful for describing discrete categories of data having multiple choice or different response formats,which involves constructing a frequency distribution.Here,the frequency distribution with intervals of 0.1kg/m3for values of the daily SSC at different stations and related statistical parameters(e.g.,the mean value,standard
Table1.Gauging stations and measured SSCSSD data.
Gauging station Position Data Collection Span/Time Duration for Measurements
Datong117.62u E,30.76u N Collected annual mean data in1955–2007,daily mean data in2000–2002,2006,and monthly mean data
from January2007to December20091
Xuliujing120.95u E,31.78u N January1999to December2000,recorded at0800and1400on each day with the average to represent the daily
mean
Collected hourly data from January to December in20062
Hengsha121.83u E,31.28u N January1999to December2000,recorded at0800and1400on each day with the average to represent the
daily mean
Collected hourly data from January to December in2006,and monthly mean data from January2007to
December20092
Sheshan121.23u E,31.42u N January1999to December2000recorded at0800,1400of each day with the mean to represent the daily mean Niupijiao122.25u E,31.13u N Collected hourly data from January to December in2006,and monthly mean data from January2007to
December20092
Nancaodong122.10u E,30.98u N Collected hourly data from January to December in2006,and monthly mean data from January2007to
December20092
Yinshuichuan122.10u E,30.98u N Collected monthly mean data from August1982to July19833
1Data from Bulletin of Yangtze River Sediment,2009.
2Data from Science Centre of Estuarine and Coastal Research in Shanghai(https://www.wendangku.net/doc/198911194.html,/).
3Data from Group of Shanghai Coastal Comprehensive Investigation,1988.
810Dai et al.
deviation)were processed by frequency statistical analysis.Moreover,the spectrum analysis can describe a signal in two-dimensional form,showing the changing characteristic over time with the frequency and phase of the signals (Xu et al.,2010).In this paper,fast Fourier transform is used to obtain the temporal characteristics of the daily mean SSC in a year at the different stations.
RESULTS
Changes of SSD into the Yangtze Estuary
The historical total runoff and SSD at Datong are shown in Figure 2.There is a mainly decennial fluctuation for runoff around a mean of 9003109m 3/y in the past 50years (Figure 2a).In general,the annual SSD shows a decreasing trend with a negative gradient over time since the 1960s.The decreasing trend was enhanced with a large gradient after 2003with the TGD operation.From the 1950s to the 1960s,
SSD remained roughly constant at 5.03108t/y.Decrease in SSD ranged from 5.03108t/y in the 1960s to 3.43108t/y in the subsequent three decades.However,the lowest annual SSD of 0.853108t was observed in 2006(Figure 2b).
Moreover,it should be noted that the daily mean SSC at the Datong in 2006is lower than that in 1999,and subsequently during 2007–2009(Figure 3a,Table 2).The seasonal change of SSC within a year can be found in 1999and 2000,as mean SSC in flood season (May to October)is higher than that in dry season,as well as during 2007–2009(Figure 3b,Table 2).However,it can be found that the annual mean SSC of 2006remained almost the same order of magnitude of about 0.1kg/m 3(Figure 3a,Table 2).The annual mean SSC at Datong after TGD construction reveals the deceasing trend in comparison with that before.The magnitude decreased from larger than 0.2kg/m 3to smaller than 0.2kg/m 3.
SSC in the Yangtze Estuary before the TGD Was Constructed
The temporal changes of daily mean and monthly mean SSC at Xuliujing,Hengsha,and Sheshan in 1999were similar to those in 2000,as shown in Figures 3c–3h.The SSC at Xuliujing in 1999and 2000shows a seasonal change with the seasonal mean of 0.19kg/m 3and 0.13kg/m 3in flood seasons larger than those of 0.11kg/m 3and 0.09kg/m 3in dry seasons (Figures 3c,3d,Table 2).However,the seasonal mean SSC of 0.32kg/m 3and 0.34kg/m 3at Hengsha in flood seasons of 1999and 2000,respectively,is slightly lower than those of 0.38kg/m 3and 0.38kg/m 3in dry seasons (Figures 3e,3f,Table 2).There is no apparent seasonal variation of SSC at Hengsha in the observed periods.However,according to Figures 3g and 3f,the daily mean SSC and monthly mean SSC at Sheshan exhibit seasonal changes with higher values of 0.51kg/m 3and 0.48kg/m 3in the dry seasons of 1999and 2000,respectively,and lower values of 0.31kg/m 3and 0.32kg/m 3in the flood seasons,which is opposite the seasonal change of SSC at Xuliujing in 1999and 2000(Figures 3g and 3f,Table 2).A similar SSC seasonal change at Nancaodong,formerly called Yinshuichuan,to that at Sheshan,can be also seen in 1982from Figures 3i and
3j.
Figure 2.Annual discharge and suspended sediment discharge at
Datong.
Figure 1.
Study area and stations.
Suspended Sediment Declining in the Yangtze Estuary 811
The annual mean SSC in 1999and 2000,as well as the seasonal mean in dry seasons,at Sheshan was larger than those at other stations before the TGD was operated (Table 2).In addition,mean SSC over seasons and a year at Nancaodong was comparable with that at Sheshan in the same period before the TGD was constructed.The mean SSC over different periods at Nancaodong in 1982is comparable with that at Sheshan in 1999and 2000.This reveals minor changes in the SSC around this area in the last two decades despite the large upstream SSD reduction,as the SSD at Datong decreased by 903106t in the 1990s compared with the 1980s,which agrees with the previous research (Chen et al.,2006).
Table 3shows the cyclical period of the daily mean SSC at stations.The table shows a clear spring–neap cycle of SSC with a period of half a month.In addition to the spring–neap cycle,a period of 9days is also visible.The spatial characteristics of the annual mean shows an increased trend in seaward direction,reaching a maximum at the mouth bar,e.g.,increasing
from
Figure 3.The daily and mean monthly SSC at the stations.
812Dai et al.
0.13kg/m3at Xuliujing to0.31kg/m3at Hengsha and Sheshan in the flood season1999(Table2).This becomes even more prominent in the dry season from0.11to0.48kg/m3. Moreover,a frequency analysis of13SSC grades with an interval of0.1kg/m3is applied to discern the frequency of the different daily mean SSC levels.Figure4a indicates that the daily mean SSC at Datong in1999was in the range of 0.1–0.3kg/m3,with the frequency accounting for over75%. Figure4b shows that the daily mean SSC values at Xuliujing in 1999mainly varied in the range of0–0.1and0.1–0.2kg/m3, with the frequency accounting for about52%and35.5%, respectively.The frequency distributions of the daily mean SSC at Hengsha and Sheshan are similar(Figures4c and4d). The dominant daily mean SSC levels at both Hengsha and Sheshan differ from those at Xuliujing(Figures4b–d).During most time in1999,the daily mean SSC at Hengsha and Sheshan were about0.2–0.3,0.3–0.4,and0.4–0.5kg/m3with the total occurrence of72%and60%,respectively.Obviously, from the upper part of the Yangtze Estuary to the mouth bar, the more seaward the location,the larger the variation of the SSC.
Meanwhile,the correlation between the monthly mean SSC at the stations and the monthly mean discharge and SSD at Datong is shown in Figures5and6.We can find a positive correlation between the monthly mean SSC at Xuliujing and the upstream discharge,but negative correlation at the other stations before the dam was constructed(Figure5).A negative correlation between the monthly mean SSC at Hengsha and the monthly mean SSD at Datong can be obtained in1999,as shown in Figure6.A negative correlation between the monthly mean SSC at Sheshan(the outer side of the mouth bar)and the monthly mean SSD at Datong can also be obtained in1999 (Figure6),as Sheshan is also located in the winter estuary turbidity maximum(ETM)zone in1999.However,a positive correlation in2006can be found between the monthly mean SSC at the outer side of mouth bar and the monthly mean SSD at Datong,according to Figure5.
SSC in the Yangtze Estuary after the TGD
Was Constructed
An apparent decrease in the monthly mean SSC at Datong, Xuliujing,and Hengsha can be found in2006compared with the other years,according to Table2and Figure3,although no clear seasonal variation can be observed from Figures3d and 3f,similar to before the TGD was constructed.However,the seasonal and yearly mean SSC at Hengsha durng2007–2009 are comparable with those during1999–2000(Table2),even though there is a decreasing trend in SSD and SSC into the Yangtze Estuary in corresponding years,as well as those observed at Niupijiao and Nancaodong(Figure2,Table2). From Table2,we observe that the mean SSC in the flood season at Niupijiao is larger than in the dry season,which is opposite the nearby station,Sheshan,before the TGD was constructed(Figures3g and3h).Similar seasonal characteris-tics of the monthly mean SSC at Nancaodong and Niupijiao can be found in2006–2009from Figure3and Table2,although they had opposite seasonal variations in1982,before the TGD was constructed(Figures3i and3j).
Table3shows that the periodicity of the daily mean SSC in the estuary was about15–17days in2006.The periodicity of half the spring–neap cycle(7–9days),which was found before the TGD was constructed,could not be found.
The same spatial characteristics of the annual mean SSC after the TGD was constructed can be found with an increasing trend toward the sea up to the mouth bar(Table2).However, the annual mean SSC at Xuliujing and Hengsha were respectively much smaller in2006than in1999,as were its standard deviation and coefficient of variation(Figures4b and 4g,4c and4h).The annual mean SSC at the outer side of the mouth bar,at Nancaodong and Niupijiao,in2006,as well as their standard deviations and coefficients of variation,were larger than those at the inner side(Figures4e,4h,and4i),as indicated by the large deviation of the daily values of SSC at these two stations.
Moreover,Figures4b and4g indicate that the daily mean SSC variation at Xuliujing in2006was smaller than in1999,as well as that at Hengsha(Figures4c and4h).The occurrence possibilities of daily mean SSC of0.1–0.2kg/m3were about96% and48%of the time in2006at Xuliujing and Hengsha, respectively.In contrast,the larger variation of SSC at
Table2.Mean SSC in different periods of a year at stations.
Period
Datong(kg/m3)Xuliujing(kg/m3)Hengsha(kg/m3)Sheshan(kg/m3)Niupijiao(kg/m3)Nancaodong(kg/m3) FS DS Whole FS DS Whole FS DS Whole FS DS Whole FS DS Whole FS DS Whole
19990.330.090.210.130.090.120.320.380.340.310.510.41///0.2**0.52**0.36** 20000.440.120.280.190.110.150.340.380.350.320.480.40////// 20060.120.090.110.10.070.080.240.240.24///0.680.400.540.890.520.71 20070.220.140.18///0.280.320.30///0.810.310.550.730.420.58 20080.180.100.16///0.320.330.32///0.380.360.370.810.480.65 20090.170.120.14///0.270.290.28///0.500.380.440.690.520.62 Numbers with‘‘**’’are the mean monthly SSC observed from August1982to July1983at the Yinshuichuan.
FS5flood season of May–October;DS5dry season of November–next April;Whole5the period of the whole year.
Table3.Cyclical period of the daily mean SSC at the stations.
Year Gauging Station Cycle Time(d)
1999Xuliujing9.214.5
Hengsha8.915
Sheshan9.215.2
2006Xuliujing14.5
Hengsha15
Nancaodong16.5
Niupijiao17.2
Suspended Sediment Declining in the Yangtze Estuary813
Nancaodong and Niupijiao was found in 2006in comparison with that at the outer side of the mouth bar (Sheshan)in 1999from Figures 4d,4e,and 4i.In addition,the monthly mean SSC around the mouth bar in the Yangtze Estuary,especially at the outer side of the mouth bar,remained at the same level,if we compare the monthly mean SSC at Nancaodong in 1982(Figure 3j)with that at Sheshan in 1999(Figure 3h),despite the large reduction of upstream SSD in the 1990s compared with the 1980s.
DISCUSSION
Correlation between the Monthly Mean SSD at Datong and the Monthly Mean SSC in the Eestuary
Our analysis indicates a positive correlation between the monthly mean SSD at Datong and monthly mean SSC at Xuliujing,as shown in Figure 5.This could imply that the upstream sediment supply is one of the important factors affecting the SSC change in the inner part of the Yangtze Estuary.However,although the large reduction of SSD in the
1990s compared with the 1980s occurred,the relatively constant SSC around the mouth bar in the Yangtze Estuary,especially at the outer side of the mouth bar area,remained in recent decades when compared with the mean monthly values of SSC at Nancaodong in 1982with that at Sheshan in 1999(Figure 3).Similarly,relatively constant SSC was also ob-served at Niupijioa and Nancaodong during 2007–2009,even though there is decreased trend in SSC at Datong in these years (Table 2).This implies that,in addition to the upstream sediment supply,other factors,such as the local sediment supply in the estuary,are also important for maintaining the SSC level.Moreover,the positive correlation between the monthly mean discharge at Datong and monthly mean SSC at Xuliujing shows that the upstream discharge has some influence on the SSC changes in the estuary.However,there is a weak relationship between the monthly mean SSC in the estuary and the upstream discharge.The discharge in 2006with minor seasonal variations due to the dam has less influence on the SSC changes in the estuary (Dai et al.,2008),which agrees well with the argument of Gao and Wang
(2008).
Figure 4.SSC occurrence at stations in 1999and 2006(Fq:frequency curve;CF:cumulative frequency curve;M:monthly mean;Sd:standard deviation;Cv:variation coefficient,Cv 5Sd/M,representing the deviation of the SSC from the monthly mean).
814Dai et al.
In reality,the upstream sediment supply in 2006reached the historical lowest level,with SSD of 853106t (Figure 2)at Datong,accounting for one quarter of the multiyear mean value.This resulted in the annual mean SSC at the inner side of the mouth bar,at Hengsha,in 2006accounting for two-thirds of that in 1999(Table 2).As pointed out by Yang et al.(2007),the Yangtze Delta suffers from erosion when the SSD at Datong is below about 1513106t.Therefore,there can exist a threshold of upstream sediment supply for the change in the SSC in the inner part of the estuary,as the SSC changes and the inner side of the mouth bar of the estuary is not sensitive to the upstream sediment supply,unless the SSD at Datong reaches its threshold.Thus,although the SSD at Datong continued to decrease since the 1990s without reaching this threshold value,the annual mean SSC remains the same level in the estuary as that when TGD was constructed.In 2006,the SSD at Datong could be below the threshold,as a consequence of the SSC lower than before.Further study is still needed to fully understand to what degree the SSD decrease reached threshold,which can induce obvious decline of SSC near the mouth bar area.
Influence of the Shift in ETM Zone
Besides the influence of the upstream SSD,other factors,such as mixing of salt water and freshwater,tides,waves,and winds,can also affect the SSC change in estuary (Chen et al.,1999;Li et al.,1999).The interaction of the river and sea results in the shift of the ETM zone with seasonal changes in upstream
discharge.In the Yangtze Estuary,the ETM zone shifts seaward in the summer due to strong freshwater discharge,and landward in the winter (Shi,2002;Shi and Kirby,2003).It means that the SSC change around the ETM zone can be sensitive to such ETM shifting caused by the seasonal runoff into the Yangtze Estuary.
Dyer (1997)also pointed out that the SSC changes in the stratified water of the ETM zone are higher than those of the other estuarine zone because of the frequent internal entrain-ment that occurs in the layer between the freshwater and salt water,advection and flocculation,desolation and resuspension.Therefore,Hengsha,located in the dry-season ETM zone,has a higher SSC,as expected in the dry season,and lower one in the flood season (Table 2).In contrast,both Nancaodong and Niupijiao have related higher SSC in flood season than those in dry season,because these two stations are located in the flood-season ETM zone due to shifted ETM by runoff pushing (Table 2).
The change of the relation between the monthly mean SSC changes at the outer side of mouth bar and the monthly mean SSD at Datong is due to the shifting of the ETM zone because of a change in flow regime,caused by the TGD regulation and an extreme drought event in 2006.Both the flow regime change and the extreme drought event resulted in the much weaker river discharge (Dai et al.,2008),as the ETM zone could not be pushed as far outward as usual.This led to a more uniform and lower SSC than that in 1999at Hengsha (Figures 3e and 3f).The outer side of the mouth bar might have remained in the ETM zone throughout 2006,unlike in 1999.It deserves
further
Figure 5.Relationships between the discharge at Datong and the SSC at the other station.
Suspended Sediment Declining in the Yangtze Estuary 815
analysis by modeling on the relationships between the SSC variations in the ETM zone and flow regime changes.Thus,the seasonal ETM zone shifting due to the flow regime change and extreme climate events can induce a SSC change in the estuary.
Periodicity of the SSC
The cyclical period of daily mean SSC with a cycle of 15–17days in 1999(Table 3)could be related to tidal movements.The tidal current had received attention as regards sediment transport and resuspension in the estuary (Chen et al.,2006;Dyer,1997;Esima,1993).Strong tidal currents in the spring tide lead to higher SSC,with sediment being suspended due to the large velocity of the water.Consequently,the periodic SSC change is synchronous with the spring–neap tidal cycle in the Yangtze Estuary.However,the weaker periodic cycle of 8–9days (Table 3)of the SSC can be related to tidal pumping (Dyer,1997)and relative increases of the riverine flow currents in neap tides with plenty of discharge available before the TGD was constructed.A periodicity of the SSC with a cycle of 15–17days is also obtained in 2006,except for the shorter periodic feature due to much weaker riverine processes compared with that before the TGD was constructed.
Influences of Waves and Storms on the SSC
The stations Shenshan,Niupijiao,and Nancaodong are located outside the mouth bar,and are directly influenced by
the waves and winds from the East China Sea.Waves with a height of about 0.6m can easily resuspend sediments at the bottom around this area with a water depth of about 5m (GSICI,1988).Relatively high wave heights occurred in 2006at Niupijao corresponding to a relatively large SSC (Figures 3and 7a)(Yan et al.,2011).Further correlative analysis indicates that there was a positive correlation between the daily wave height and the daily SSC at Niupijiao in 2006(Figure 7b).It is clear that sediments located in the mouth-bar zone area will be moved,with intense resuspension due to wave action (Li and Zhang,1998;Yan et al.,2011).In contrast,in the landward direction,the wave energy is dissipated quickly due to bottom friction and breaking on the mouth bar,resulting in the higher SSC outside the mouth bar compared with inside the estuary,e.g.,at Hengsha and Xuliujing (Table 2).
In the flood season,the typical monsoons,typhoons,frequently affect this area,resulting in large wave heights on the outer side of the mouth bar.Especially in 2006,several severe typhoons from the southeast affected the estuary.During these typhoon periods in August and October 2006,the maximum wind speed in the estuary exceeded 24m/s,accompanied by large waves,resulting in the high SSC at Nancaodong and Niupijiao in these months (Figure 3).This can also partly explain the positive correlation between the SSC in this area and the SSD at Datong after the TGD was constructed,compared with the negative correlation that existed previously (Figure 6).Moreover,as various
dynamic
Figure 6.Relationship between the SSD at Datong and the SSC at the other station.
816Dai et al.
processes,such as tides,discharge,waves,winds,and flocculation,are involved,the SSC varies in a larger range on the outer side of the mouth bar than inside (Figure 4).These are also essential for further investigation on the SSC change in the estuary.
CONCLUSIONS
The SSC changes in the estuary can play an important role in the geochemical cycle,contaminant migration,and biological adsorptions.Analysis of the SSC changes in the estuary is one of the important factors to water environment management and shore protection.By using comparative methods,we analyzed two SSC data sets in recent years,representative for the conditions before and after the operation of TGD to discuss the SSC change near the mouth bar of the Yangtze Estuary.Meaningful conclusions are shown as follows:(1)The annual mean SSC at the inner side of the mouth bar
are lower after the TGD was constructed than before,due to the SSD reduction upstream.However,at the outer side of the mouth bar,the annual mean SSC was comparable with that before the TGD was operated.
(2)Spatially,the annual mean SSC in the Yangtze Estuary
increases from the upper part (Xuliujing)to the mouth bar.The tidal force apparently influences the SSC in the estuary,with the periodic characteristics of the spring–neap cycle.
(3)The monthly mean SSC around the mouth bar of the
Yangtze Estuary is not sensitive to the upstream SSD,except that the SSC at the inner side is sensitive to the threshold low-sediment supply from upstream.
(4)The shift of the ETM zone due to seasonal variation of
river discharge causes seasonal characteristics of the SSC near the mouth bar.The SSC at the inner part of the mouth bar is lower in flood season than that in dry season,and SSC at the outer side of the mouth bar was higher in flood season than that in dry season.
ACKNOWLEDGMENTS
This study was supported by the National Science Foun-dation in China (contract number:41021064,50939003,50979053),the Funds for Ministry of Science and Technology of China (SKLEC:2010RCDW03),and the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.We gratefully acknowledge two anonymous reviewers for commenting on the preliminary paper.
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河道生态修复基础
河道生态修复基础知识 一、概况 河道生态修复是指在生态学原理基础上，使用综合方法，改善水文条件和河道地貌学特征，修复受损伤的水生态系统的生物群体及结构，重建健康的水生生态系统，修复和强化水体生态系统的主要功能，并能使生态系统实现整体协调，自我维持、自我演替的良性循环。 城市河道生态修复是根据自然生态系统多样性的要求，恢复河道自然属性，改变因城市化和传统水利工程所造成的河道的非自然面貌，消除因此带来的生态胁迫，为河道内及滨河的生物重新构建栖息场所，使得生态系统恢复到接近自然的状态，从而恢复城市河道各种功能，保持河道健康。 二、世界河流生态修复进展
世界上许多国家都在进行河道重返自然的生态修复。从上世纪70 年代起开始，发达国家针对人类活动干扰对河道生态系统的负面影响，开发了河道生态修复的理论和技术。并在河道整治工程和堤防工程设计、施工规范中增加了河道生态建设的内容，或颁布了专门的河道生态工程设计导则。 目前，国外河道生态修复技术包括以下：根据“给河道以空间”的洪水管理理念，建设分洪道、降低河漫滩高程；恢复河道连续性和蜿蜒性；河道岸坡生态防护；重建深槽和浅滩序列；恢复洪泛区湿地；创建河道内生物栖息地结构；建设亲水设施；应用多孔和透水护岸材料和结构等。同时，利用生态学理论，采用生态技术修复受污染河水，恢复水体自净能力，如：人工湿地处理系统、河道直接净化技术、氧化塘处理系统、植物——土壤处理系统、水生植物处理系统、生物操纵技术等 1）德国的近自然河道治理工程 德国的Selferr 首先提出近自然河溪治理的概念。它是指能够在完成传统河道治理任务的基础上，接近自然、经济并保持景观美的一种治理方案1。20 世纪50 年代，德国创立了“近自然河道治理工程”，提出河道的整治要符合植物化和生命化的原理。70 年代中期，德国进行了称之为“重新自然化”关于自然的保护与创造的尝试，开始在全国范围内开始拆除了被砼渠道化了的河道，将河道恢复到接近自然的
【CN110104913A】一种底泥修复剂及其应用于底泥原位修复的方法【专利】
(19)中华人民共和国国家知识产权局 (12)发明专利申请 (10)申请公布号 (43)申请公布日 (21)申请号 201910248539.1 (22)申请日 2019.03.29 (71)申请人 浙江融信环保科技有限公司 地址 314500 浙江省嘉兴市桐乡市梧桐街 道发展大道1488号1幢2楼西间 (72)发明人 曹玉成 许佳霖 汪奇 武帅 谢成浩 苑永魁 (74)专利代理机构 浙江杭知桥律师事务所 33256 代理人 王梨华 陈丽霞 (51)Int.Cl. C02F 11/00(2006.01) (54)发明名称 一种底泥修复剂及其应用于底泥原位修复 的方法 (57)摘要 本发明涉及水污染防治与生态修复领域，公 开一种底泥修复剂及其应用于底泥原位修复的 方法，底泥修复剂由以下质量百分比的组分组 成：原生蛭石粉：25～35％；改性牡蛎壳粉：15～ 25％；改性白云石粉：20～30％；改性生物炭粉： 20～30％。发明提供的底泥修复剂，是以水生动 物源废弃物、植物源废弃物和天然矿物为原料， 经煅烧、破碎、筛分、炭化等工序处理后制备而 成，原材料来源广泛、廉价宜得，制备工序简单， 制备条件温和；生产易于规模化，应用不会产生 二次污染问题。本发明底泥修复剂，可高效抑制 底泥中污染物质的释放， 特别是对容易引发水华的氮、磷物质， 具有很好的抑制和钝化效应。权利要求书2页 说明书6页CN 110104913 A 2019.08.09 C N 110104913 A
权 利 要 求 书1/2页CN 110104913 A 1.一种底泥修复剂，其特征在于，由以下质量百分比的组分组成： 原生蛭石粉：25～35％； 改性牡蛎壳粉：15～25％； 改性白云石粉：20～30％； 改性生物炭粉：20～30％。 2.根据权利要求1所述的一种底泥修复剂，其特征在于：原生蛭石粉是由蛭石原矿粉经破碎和筛分处理制备而成，原生蛭石粉的粒径小于0.5mm。 3.根据权利要求1所述的一种底泥修复剂，其特征在于：改性牡蛎壳粉是由牡蛎壳经过煅烧、破碎和筛分处理制备而成，改性牡蛎壳粉的粒径小于0.5mm，煅烧的温度为450～650℃。 4.根据权利要求1所述的一种底泥修复剂，其特征在于：改性白云石粉是白云石经煅烧、破碎和筛分处理制备而成，改性牡蛎壳粉的粒径小于0.5mm，煅烧温度为650～670℃。 5.根据权利要求1所述的一种底泥修复剂，其特征在于：改性生物炭粉的制备过程如下： (1)将收集的废弃生物质风干、破碎、筛分，获得粒径小于2mm的生物质粉； (2)在步骤(1)得到的生物质粉中加入液态氯化镁改性剂，并充分搅拌混合得到生物质粉混合物，液态氯化镁改性剂中液态氯化镁的质量浓度为50～70％，液态氯化镁改性剂的投加量为生物质粉质量的5～10％； (3)对步骤(2)得到的生物质粉混合物进行通风热干化处理，干化温度低于150℃，待混合物料干化至含水率低于20％后，对其限氧炭化，炭化温度为400～800℃，炭化时间为1～3h。 6.一种底泥修复剂的制备方法，其特征在于，包括： 1)制备原生蛭石粉； 2)制备改性牡蛎壳粉； 3)制备改性白云石粉； 4)制备改性生物炭粉； 5)将步骤1)～4)制备的组分进行混合，按以下质量百分比计，原生蛭石粉：25-35％，改性牡蛎壳粉：15-25％，改性白云石粉：20-30％，改性生物炭粉：20-30％。 7.一种底泥修复剂应用于底泥原位修复的方法，其特征在于，包括以下措施： (1)应用于开放式河道底泥修复时，选择晴朗天气、水流相对缓慢的时间段在河道水面上投加底泥修复剂；投加时，在河道上游、河道近岸处和污水入河排放口区域的投加量为每平方米水面1～5kg，在河道下游、河道中部和雨水入河排放区域的投加量为每平方米水面0.5～1kg； (2)应用于相对封闭的天然水体时，在进水区域、水面上均匀投加底泥修复剂，投加量为每平方米水面0.5～1kg。 8.一种如权利要求1～5任意一项所述的底泥修复剂在水体底泥原位修复中应用，其特征在于，所述水体底泥是指开放式河道水体底泥；投加时，在河道上游、河道近岸处和污水入河排放口区域的投加量为每平方米水面1-5kg，在河道下游、河道中部和雨水入河排放区域的投加量为每平方米水面0.5-1kg。 2
疏浚施工方案(DOC)
第一章工程概况 一、工程概况 诸暨境内有浦阳江和壶源江两大河流，均属于钱塘江水系，其中浦阳江流域面积占全市总面积94.5%，湖源江流域占全市总面积4.95%。本次范围属于浦阳江水系。 浦阳江发源于浦江县花桥乡蛇高龄麓岭脚，主流长150km，流域面积3452km2，流经浦江、义乌、诸暨、萧山等四县（市、区）。诸暨境内干流长67.6km，流域面积2183.9km2。干流从同山镇界牌宣入境，出安华水库至安华右纳大陈江，向东北流至丫江杨，右汇开化江，北流经诸暨城区至茅渚埠，分东、西两江。西江（西浦阳江）为浦阳江主流，北流至石家祝桥左纳五泄江，继北流经姚公埠至湄池与东江合流。东江（浦阳东江）自茅渚埠分流，往东折北经五浦头，至江藻中江村右纳枫桥江，北流经三江口至湄池，与西江会合。东西江汇合后，其下至兔石头出境，入萧山区，出境后继北流至尖山镇，左汇凰桐江，经萧山临浦镇，至萧山义桥又左纳永兴河，北流到萧山孔家埠小砾山注入钱塘江。诸暨境内浦阳江主要有大陈江、开化江、枫桥江、五泄江、凰桐江等五大支流。 浦阳江流域的地形主要为低山丘陵及河谷平原，其中安华以上为浦阳江上游，安华至湄池为中游。上游源短流急，中游河道弯曲下载，下游受钱塘江洪潮顶托（诸暨城关王家堰为感潮河段，长5km）。
本码头工程位于陶朱街道新亭埠浦阳西江道左岸。根据浦阳西江航道规划要求和码头现状分析、吞吐量预测，拟建暨阳码头占地48536m2，用于建设500t级内河泊位6个，其中散货码头4个，杂货泊位1个，多用途泊位1个，年吞吐量可达162万吨。此外该项目还规划在码头上游预留41728m2作为发展区，在码头下游预留18933m2作为堆场区。 码头所在浦阳江西江河段，河道最宽可达680m左右，最窄处只有70m左右，河段左岸附近堤防高程约为13.26-13.70m，右岸附近堤防高程约为13.18-13.40m。该区域内河道主流在河道左岸，靠近码头右岸原为很大一块江滩地，是当地居民自留地，后因居民挖沙，将淘沙剩余物丢弃在河道中，日积月累在河道中形成了若干个形状不规则的江心小洲，将河道干流分成若干汊。 该码头前沿线距最近的航道边线约73m，距最近的航道中心线98m，顺水流方向长约为340m，垂直水流方向最宽达173m，内河码头及堤内陆域顶面标高规划为10.10m，堤后陆域地坪基本标高10.00m。码头所在河道按400m宽河底疏浚，其中航道底高程疏浚至1.1m，锚泊区疏浚边线按1:3疏浚。 由诸暨市经济开发总公司投资建设，合同金额约0.77亿元。工本工程于2013年3月21日开工，计划2014年10月28日竣工。 建设单位：诸暨市经济开发总公司 监理单位：上海海科工程咨询有限公司
水环境保护复习
第一章绪论 1.水环境保护的主要任务与内容： （1）水环境的监测、调查与试验，已获得水环境分析计算和研究的基础资料； （2）对排入研究水体（称受纳水体）的污染源的排污情况进行预测，称污染负荷预测，包括对未来水平年的工业废水、生活污水、流域径流污染负荷的预测； （3）建立水环境模拟预测数学模型，根据预测的污染负荷，预测不同水平年研究水体可能产生的污染时空变化情况； （4）水环境质量评价，以全面认识环境污染的历史变化、现状和未来的情况，了解水环境质量的优劣，为环境保护规划与管理提供依据； （5）进行水环境保护规划，根据最优化原理与方法，提出满足水环境保护目标要求的水污染防治最佳方案； （6）环境保护的最优化管理，运用现有的各种措施，最大限度的减少污染。 2.污染物： 水中存在的各种物质（包括能量），其含量变化过程中，凡有可能引起水的功能降低而危害生态健康，尤其人类的生存与健康时，则称他们造成了水体污染，于是他们被称为污染物。 水体污染：水中存在的各种物质，其含量变化过程中，凡有可能引起水的功能降低而危害生态健康，尤其人类的生存与健康时，则称造成了水体污染。 3.水体污染物的分类： （1）按污染物的属性分类：物理性的、化学性的和生物性的。 （2）按进入水体的污染来源分布情况分类：点源的和非点源的。 点源污染：指工业废水和城镇生活污水，他们有固定的排放口； 非点源污染：指来自流域广大面积上的降雨径流污染，如泥沙、农药、化肥等污染，常称面源污染； 线源污染：如航行的船舶的污染。 4.水污染危害 耗氧有机物污染、可溶性盐类和酸碱物质污染、重金属污染（比重大于4）、有毒化学品污染、水中悬浮固体、油类污染、热污染、放射性污染、病原微生物污染、 5.水体污染原因 自然污染：特殊的地质构造或者其他自然条件是一个地区的化学元素富集，或天然植物在腐烂过程中产生某些有毒物质。 人为污染：由于人类活动造成的污染，如工业污水不加处理排放，农药化肥随径流进入水体等。 纳污：污染物在水文循环中不断进入水体的现象。 自净：污染物随水体的运动不停地发生变化，自然地减少、消失或无害化。 6.水体自净过程： （1）物理净化过程：指污染物在水体中混合、稀释、沉淀、吸附、凝聚、向大气挥发和病菌死亡等物理作用下使水体污染浓度降低的现象； （2）化学净化过程：指污染物在水中由于分解与化合、氧化与还原、酸碱反应等化学作用下，致使污染浓度降低或毒性丧失的现象； （3）生物净化过程：是水体内的庞大的微生物群，在他们分泌的各种酶的作用下，使污染物不断发生分解和转化为无害物质的现象。 7.水的自净能力：水的污染物浓度自然降低而恢复到较清洁的能力。
黑臭水体底泥原位治理技术研究
黑臭水体底泥原位治理技术研究 摘要：在我国现阶段的城市中，污染非常严重，经常会有黑臭水体出现。随着 外源污染逐步得到有效控制，治理底泥内源污染已成为改善黑臭水体水质的关键，直接影响河道治理效果。为了从根本上治理黑臭水体，必须控制河道底泥污染， 防止水体返黑、水质反复恶化。异地处理技术（如疏浚底泥）应用较广，但存在 工程量大、治理费用较高、处置过程中存在二次污染、底泥后续处理困难等问题，而底泥原位治理技术具有治理费用低，对河道水体二次污染和河道治理效果好等 优点，受到广泛关注，并逐渐成为底泥污染治理的研究热点。针对城市黑臭水体 处理现状，介绍了原位覆盖处理、化学处理以及生物修复3种黑臭水体底泥原位 治理方法的机理和修复效果，以期为治理城市黑臭水体提供借鉴。 关键词：黑臭水体；底泥污染；原位治理；生物修复 引言 黑臭水体不仅严重影响了城市的水景观，给人带来不愉悦的观感；丧失水体 功能性，抑制了人们的亲水和取水需求，同时还影响周围居民的身体健康，对人 们的呼吸系统、循环系统、消化系统都有不良影响。因此，解决城市河流的污染 问题、恢复河流的生态和社会功能不仅关乎城市整体形象的提升，更是与居民健 康和生活息息相关，是十分必要且迫切的。 1城市黑臭水体危害分析 在探讨城市黑臭水体治理问题和相关技术前，我们首先需要明确黑臭水体的 来源、构成，并且分析其造成的极大危害。城市黑臭水体之所以会产生，其根源 在于大量城市生活污水和工业废水被肆意排放，未经过相应处理。这些水体中存 在过量污染物质，而微生物在这些污染物中肆意繁殖，消耗大量氧气，水体逐渐 呈现缺氧状态。在这种条件下会进一步导致各种厌氧微生物的繁殖，这会使得水 体中有机物迅速腐烂随之发酵，这就会产生很多氨气，硫化氢及甲烷等具备恶臭 的有毒有害气体，这也是水体臭味的来源。而水体中的金属离子又会进一步和水 体中存在的硫离子发生反应，生成FeS或MnS这些黑色物质，这便是我们看到水体呈黑色的造成原因。城市黑臭水体无论是对自然环境还是人们的生活环境都具 备极大危害。首先，黑臭水体的存在会严重影响自然生态环境，在污染空气，破 坏市容的同时也会对于其他生物的生存构成恶劣影响。另一方面，城市黑臭水体 中会产生大量挥发性有毒气体，比如硫化氢就是其中一种。这种气体对于人体有 严重毒害作用，达到一定剂量后甚至会有致命危险。因此，城市黑臭水体必须得 到尽快治理，并且要得到积极有效治理，这才会营造良好的社会环境和城市生活 环境，才不会影响到城市居民的生活质量。 2黑臭水体治理技术 2.1原位覆盖技术的应用 目前，原位覆盖技术的施工方式主要有以下几种：机械设备表层倾倒法、移 动驳船表层撒布法、水力喷射表层覆盖法、驳船管道水下覆盖法。国外运用覆盖 技术进行底泥污染释放的控制工程很多。此技术在我国研究开展较晚，应用并不 广泛，大多停留在实验室阶段，存在巨大前景。目前，我国已有学者在研究新的 覆盖材料，如李杨等将芦竹茎、芦苇茎、花生壳及玉米芯利用限氧升温炭化法烧 制成的生物炭可以提高底泥的硝化作用强度，对底泥NH4+-N、COD及PO34--P的释放有削减作用，具有应用到污染水体底泥修复的潜力。 2.2清淤疏浚
吹填施工方案(吹沙土)
施工方案
二O一一年十二月十八日 1、工程概况： 拟运土总量约192万方 2、施工组织措施 ⑴、本工程我公司将由公司经理、公司总工程师具体负责工程施工的后勤保障工作，及施工技术指导质量方案审查等事宜，全面开展并协调项目经理部、公司各职能科室、施工人员的选派及机械设备的配合工作，下设质量负责、安全负责及机械负责专门人员，对工程施工技术质量安全具有指导监督的权利。 ⑵根据本工程特点及进度、工程质量、安全与文明施工的需要选择政治素质好、技术水平高和身体健康的人员组成吹填工程项目部。项目经理部由项目经理、技术负责人、项目生产副经理组成领导层，实行项目经理负责制。 ⑶项目经理及项目部管理人员由一专多能、精明强干、具有同类工程及丰富的水利工程施工经验的人员担任。项目经理、副经理，负责整个项目的施工进度、生产质量、技术、安全、机械、材料的供应和各工种之间的协调工作。技术负责人负责与业主、设计单位及监理的配合工作，以确保工程质量和工程顺利开展。各专业技术人员在项目经理及技术负责人的领导下具体负责相关事宜，并利用晚上休息的时间建立每周技术质量生产行政例会、每日碰头会制度，定期向建设单位、监理、、送土单位、公司领导报送工作简报及施工中存在的问题，以便各有关领导及时了解项目进展情况，及时对工程项目施工给予指导、支持，同时积极听取业主意见，接受业主监理指令，服从有关部门监督，保证工程顺利进行，工程质量符合要求。 3、施工现场布置 按业主指定的地点布置吹砂船以及施工附属设施，工人生活用房使用生活船，吹填用电利用吹砂船自发电。 4、施工平面布置原则 总体布置思想：考虑全面周到，布置合理有序，方便施工，便于管理，利于文明施工，标准适度，能体现文明工地的形象。 施工区域沿河岸设立标语、彩旗，工地竖立工程简介，书写规范，用语文
河道整治及生态修复监理细则
淮安市白马河上游九条河道整治及生态修复工程 监 理 细 则 监理单位：江苏省工程勘测研究院有限责任公司洪泽县白马湖生态保护项目监理部 日期：2016年11月22日
施工监理实施细则 说明： 1.本细则依据工程承建合同文件、设计文件以及《水利水电工程施工监理规范》SL288－2014、《水利工程建设标准强制性条文2016版》等有关工程规范编制。 2．编制单位：江苏省工程勘测研究院有限责任公司洪泽县白马湖生态保护项目监理部 批准人： 编制人： 洪泽县白马湖生态保护项目监理部 日期：2016年11月22日
施工监理实施细则 1、总则 1.1本细则依据工程承建合同文件及有关工程规程规范和技术标准编制。 1.2 本细则适用于水利水电工程建筑材料的质量监理。 2、承包人的责任 2.1承包人应向监理提交建筑材料的采购合同、出厂质量证明、出厂合格证和出厂试验报告。 2.2承包人必须按合同的有关规定建立检测试验室或委托有资质的检测单位，对施工中采用的建筑材料进行自检取样试验，并按规定将试验报告报送监理审查和核备。 2.3监理可按监理合同规定或项目法人要求对建筑材料进行抽检试验，承包人应为监理的抽检试验提供方便。 2.4承包人计划使用代用材料时，应报送监理审批。 2.5承包人应对提供使用的所有材料负全部责任。一旦发现使用不合格的材料，应按监理指示予以更换并将不合格的材料运离工地，并承担由此造成的一切损失和合同责任。 2.6承包人未按规定进行建筑材料的质量检验而造成施工进度延误的，由承包人承担合同责任。 3、申报签证程序
3.1建筑材料进场前，承包人应按合同有关条款规定，将拟选择的有生产许可证的厂家，采购或使用计划，一并报监理审查批准后方可实施。 3.2在建筑材料进场前，承包人应按规定，进行检测试验，并向监理报送《进场材料报验单》。 3.3上述报送文件连同签审意见单均一式四份，经承包人项目经理签署并加盖公章后报送监理部，监理部在检查合格后予以签证确认，承包人方可使建筑材料进场。 3.4 如果承包人未能按期向监理部报送上述文件时，由此造成施工工期延误和其他损失，均由承包人承担合同责任。 4. 质量检验程序 4.1钢筋与型材 4.1.1钢筋与型材，生产厂家应有生产资质和生产许可证，每批应有出厂日期、生产合格证及产品质量检验报告。 4.1.2钢筋使用前，按同品种、同等级、同炉号、同厂家生产每60t一批（不足60t的按一批）验收，每批至少取样一组，做抗拉及冷弯试验。 4.1.3钢号不明的钢材，经试验合格后方可使用，但不能在承重结构的重要部位上使用。对钢号不明的钢材进行试验，其抽样组数不得少于6组。 4.1.4钢筋的焊接方法应符合有关规程规范，对使用的不同品种、钢号、直径的钢筋之间焊接均需至少进行一组焊接强度试验。
铬污染土壤固化／稳定化技术工程应用研究
铬污染土壤固化/稳定化技术工程应用研究 [摘要]我国是世界铬盐生产大国，每年产生大量的铬渣，铬渣堆放对土壤环境造成严重污染。国家”十二五”规划明确提出了重点地区铬污染土壤的治理目标，铬污染土壤的治理工作正迅速展开。固化/稳定化技术工艺操作简单、处理时间短、固化剂易得，目前在我国70%以上铬污染土壤治理工程中得到应用。本文通过铬污染土壤固化/稳定化技术工程应用环节的研究探讨，分析总结实施过程中的存在问题，并对该技术的工程应用提出展望。 [关键字]铬污染土壤固化稳定化技术工程应用问题与展望 1铬污染土壤固化/稳定化技术工程应用背景 我国是世界铬盐生产大国，年产量超过60万吨，在其生产过程中产生大量铬渣。铬渣中含有0.3-1.5%可溶性Cr（VI），经降雨和地表水的冲刷，Cr（VI）进入周围土壤和地下水，对环境造成严重污染。国家环境保护”十二五”规划中，将铬渣堆场列为我国土壤重金属污染重点治理对象。 铬在土壤中一般以两种价态存在，Cr（VI）和Cr（III）。Cr（VI）以易溶于水的铬酸根（CrO42-）和重铬酸根（Cr2O72-）存在，在土壤和地下水系统中迁移性很强。Cr（VI）对于细胞具有较强的穿透能力，还有较高的氧化能力，对生物体有较强的毒性和致癌作用。Cr（III）是高等动物必须的微量元素之一，高浓度下也有一定的毒性，在一般地下水环境中不易移动。 铬污染土壤治理有堆肥技术、电动修复技术、生物修复技术、热解还原技术、淋洗技术、固化/稳定化技术[1]。综合这些技术的可靠性、可操作性、治理时间和成本，目前工程中应用最多的是固化/稳定化技术。美国环保署将固化/稳定化技术称为处理有毒有害废物的最佳技术，1982-2005年间，美国超级基金共对977个场地进行修复或拟修复，其中217个场地修复使用固化/稳定化技术[2]。在我国，固化稳定化技术是工程中常用的修复技术，铬污染土壤治理中应用达70%以上。 2.铬污染土壤固化/稳定化系统设计 2.1铬污染土壤的固化/稳定化系统 铬污染土壤的固化/稳定化包括两个过程：稳定化和固化。稳定化是将六价铬还原为三价铬，降低铬在环境中的迁移性和生物可利用性，从而降低铬污染的危害。固化是将被铬污染的土壤与某种粘合剂混合通过粘合剂固定其中的铬，使铬不再向周围环境迁移。 在铬污染土壤固化/稳定化技术系统设计中，需要综合考虑氧化还原、胶凝固化、吸附三方面因素，铬污染土壤固化稳定化系统设计中常用的药剂有：
水库河道整治工程 库区生态保护工程以及水环境修复工程方案
目录 1概述.......................................................................... 错误!未指定书签。 1.1项目背景 ........................................................................ 错误!未指定书签。 1.1指导思想 ........................................................................ 错误!未指定书签。 1.2基本原则 ........................................................................ 错误!未指定书签。 1.3编制依据 ........................................................................ 错误!未指定书签。 1.4实施范围及目标 ............................................................ 错误!未指定书签。2水环境概况 ............................................................. 错误!未指定书签。 2.1项目区概况 .................................................................... 错误!未指定书签。 2.2...口水库概况 .................................................................. 错误!未指定书签。3问题诊断 ................................................................. 错误!未指定书签。 3.1目标要求 ........................................................................ 错误!未指定书签。 3.2存在问题 ........................................................................ 错误!未指定书签。 3.3现状评价 ........................................................................ 错误!未指定书签。4绩效目标 ................................................................. 错误!未指定书签。 4.1生态环境效益目标与指标 ............................................ 错误!未指定书签。 4.2投融资效率目标与指标 ................................................ 错误!未指定书签。 4.3管理效力目标与指标 .................................................... 错误!未指定书签。 4.4社会效应目标与指标 .................................................... 错误!未指定书签。5技术路线与措施 ..................................................... 错误!未指定书签。 5.1河道整治工程 ................................................................ 错误!未指定书签。 5.2库区生态保护工程 ........................................................ 错误!未指定书签。 5.3水环境修复工程 ............................................................ 错误!未指定书签。6效益分析 ................................................................. 错误!未指定书签。 6.1社会效益 ........................................................................ 错误!未指定书签。 6.2经济效益 ........................................................................ 错误!未指定书签。 6.3生态环境效益 ................................................................ 错误!未指定书签。
土壤固化稳定化技术路线
土壤重金属污染固化/稳定化治理技术 一、基本概念 固化/稳定化土壤修复技术指运用物理或化学的方法将土壤中的有害污染物固定起来，或者将污染物转化成化学性质不活泼的形态，阻止其在环境中迁移、扩散等过程，从而降低污染物质的毒害程度的修复技术。 固化/稳定化技术与其他修复技术相比，有费用低、修复时间短、可处理多种复合重金属污染、易操作、适用范围较广等优势，因此，美国环保署将固化/稳定化技术称为处理有害有毒废物的最佳技术。 二、常用的固化/ 稳定化技术系统 目前，常用的固化/ 稳定化技术主要包括以下几种类型：（1）水泥、石灰、粉煤灰等无机材料固化；（2）沥青、聚乙烯等热塑性有机材料和脲甲醛、聚酯等热固性有机材料固化；（3）玻璃化技术；（4）硫酸亚铁、磷酸盐、氢氧化钠、高分子有机物等药剂稳定化。由于技术和费用等方面的原因，以水泥、石灰、粉煤灰等无机材料为添加剂的固化/ 稳定化应用最广泛，占项目数的94%，在项目中使用无机-有机复合添加剂的占项目数的3%。 1、水泥固化 水泥基粘结剂是固化技术普遍使用的材料。在过去的50 年里水泥固定化处理重金属技术被广泛使用。水泥是一种无机胶结材料，经过水化反应后可以生成坚硬的水泥固化体。水泥固化的机理主要是在水泥的水化过程中，重金属可以通过吸附、化学吸收、沉降、离子交换、钝化等多种方式与水泥发生反应，最终以氢氧化物或络合物的形式停留在水泥水化形成的水化硅酸盐胶体表面，同时水泥的加入也为重金属提供了碱性环境，抑制了重金属的渗滤。 水泥的种类很多，包括普通硅酸盐水泥、矿渣硅酸盐水泥、矾土水泥、沸石水泥等都可以作为废物固化处理的基材，其中最常用的是普通硅酸盐水泥。影响水泥固化的因素很多，为达到满意的固化效果，在固化操作过程中要严格控制水灰比、水泥与废物比、凝固时间、添加剂和固化块的成型条件等工艺参数。如果被处理废物中含有妨碍水合作用的物质，仅用普通水泥处理就存在强度不大、物理化学性能不稳定等问题，需加入适当的添加剂，以吸收有害物质并促进其凝固，并降低有害组分的溶出率。活性氧化铝具有助凝作用，是常用的添加剂，
清淤及底泥原位修复工程施工方案
清淤及底泥原位修复工程施工方案 （一）清淤施工方案 采用人工或机械清淤和水力清淤等方式。对于河道断面小、现场场地狭窄、暗涵内空间较小，不适合机械作业的地段采用人工清淤，对于现场具备机械作业条件的地段可采用机械清淤和人工配合。清淤前，需做好底泥污染调查，明确疏浚范围和疏浚深度；根据当地气候和降雨特征，合理选择底泥清淤季节；清淤工作不得影响水生生物生长；清淤后回水水质应满足“无黑臭”的指标要求。 （1）清淤实施原则 河床受河道两侧生活垃圾、生产污水影响，沉积大量泥沙、污泥，淤积严重，设计对整个河道进行清淤，清除河底垃圾及淤泥。河道清淤建议从上游向下游，先中央后两侧的顺序施工，可采取分段实施，每200m～300m左右作为一个施工段，多段同时施工，循环施工。 （2）清淤方式 由于水深较小，可采用挖掘机进行清淤施工。用挖掘机挖装至运输车，运至临时堆场沥水、固化，然后运至指定弃渣场地或利用。见图67。 图67 清淤施工图片 挖掘机在进入河道清淤时，河道内水位一般不应超过10cm，在河道内设计导流沟，将积水排出清淤河道下游。清淤时主要采取挖掘机倒运打堆形式进行，将河道内淤泥堆放在便道内侧沥水，沥水后由车辆运输出场外。 由于采用水中清淤，淤泥含水量大，运输过程中容易造成道路及周边环境污染，因此淤泥挖至河岸后需经过晾晒方可外运。
在淤泥运输车辆出入口位置设置下河坡道，每处长20m、宽5m。河道内设置临时施工便道，宽5m。外运车辆出场前在出口处派专人进行轮胎清理，避免车辆带泥出场。 （二）底泥原位修复 底泥原位修复可在基本不破坏水体底泥自然环境条件下，对富营养化的底泥进行降解和修复。底质改良型环境修复剂是具有多年工程运行经验的固载化的复合微生物制剂，能够在激活原有底泥环境中土著微生物的同时，引入多种特效微生物及其生长所需要的营养来提高生物活性，因而可在原地快速分解黑臭污泥中的多种污染物，减少底泥内源污染。 （1）底泥原位修复技术的优点： 1）受污河水和污泥同步治理，快速消除黑臭现象； 2）河道及湖泊和水库中的污泥处理后污泥的氧化还原电位增加数倍，污泥被减量2/3左右，河道的库容量增加，污泥中的重金属被固化，基本达到土壤耕作要求,实现黑臭河流的生态修复，标本兼治，不产生二次污染； 3）具有淤泥去除、水质净化和底泥恢复活性三种功能合一； 4）水质经过处理后，新增污染源不超过自净能力能达到国家III～V类水标准，且能长期保持水质； 5）运行稳定，投资和运行成本低，维护简便。 底泥修复效果如图68。 图68 底泥修复前后对比图 底泥改良过程如图69。
河道生态修复专题报告
河道生态修复专题报告 1、砂坑治理 沙坑的成因分析 导致沙坑形成的原因有人为和自然两种因素，人为的挖沙取石是沙坑形成的主要原因，不合理的开采利用，破坏地表植被，直接导致沙坑形成。同时风蚀、水蚀也加剧了沙坑的形成。 沙坑的特点分析：一般分布较广、且多数比较零散。 沙坑的危害 （1）破坏土地、影响地表景观。 砂石的开采是以剥离挖损土地为主，显着改变了地表景观，一般沙坑开采前是有植被覆盖的河滩地，甚至是农田。开采后地貌和植被遭到破坏，由于沙石的挖去，地面形成巨大的沙坑，且周围堆置着大量的废石与垃圾，严重破坏地表自然景观，形成一个与周围环境完全不同甚至极不协调的外观。随着人类社会的发展与进度，景观的破坏越来越多的引起当地居民的强烈反应。 （2）形成大量沙尘源，容易就地起砂。 沙坑多分布在生态环境原本就很脆弱的河道两侧及荒滩地。由挖沙取石，破坏了植被和表层土壤，形成大面积的荒沙地。到了冬春季节，风起沙扬。 （3）造成大量的水土流失。 人工采石挖沙，形成沙坑，造成周边地段地下水下降，加上人工对地面的扰动，使土壤的抗侵蚀性降低，到了雨季，加剧水土流失，并容易引起塌方等自然地质灾害。 总之，由于砂石的开采，沙坑的形成，破坏了生态环境，污染了大气环境，严重影响了社会经济的发展和人名的生活水平。 沙坑治理的具体措施 (1)大沙坑治理采取小坡平整的措施 1)平整最小边坡1:5。根据植被生长需要及稳固沙土要求，植被自然生长所需坡度不宜陡于1:5。 2)尽量保证堤脚护堤滩地宽度不小于30m。 3)基本保证每一个横断面内，挖填土方内部平衡，且就近平衡。 (2)有常流水的河道，采取引种水草、封河育草的措施，恢复河道的湿地景观。 (3)干旱河道采取撒播草籽的措施，提高河道内的植被盖度，减少水土流失，避免扬沙。 2、土壤改良 针对不同土壤质地类型，提出相应的土壤改良措施模式： （1）河道基质为砾石类占主体的地段：首先将河道局部小地形地貌平整处理，然后覆盖一层3-5cm层厚的生土，并碾压2-3次，压实，形成一个隔水层。其次将河道内的沙土按照1:1的体积比例与客土进行混合配置。主要客土材料配比为：黄壤土60%，有机质（泥炭和农家肥总计15-20%）+植物纤维（粉碎的农作物秸秆20%-25%）。增加适当的土壤改良剂及保水剂，配好的客土覆盖20cm厚度。 （2）沙质土类为主体的地段：河道平整处理，然后覆盖一层3-5cm层厚的生土，并碾压2-3次，压实，形成一个隔水层。将河道内的沙土按照4:3的体积比例与客土进行混合配置。主要客土材料配比为：黄壤土60%，有机质（泥炭和
河道生态修复与建设施工方案[优秀工程方案]
目录 1概述 (3) 1.1项目背景 (3) 1.1指导思想 (3) 1.2基本原则 (4) 1.3编制依据 (4) 1.4实施范围及目标 (5) 2水环境概况 (6) 2.1项目区概况 (6) 2.2...口水库概况 .. (8) 3问题诊断 (10) 3.1目标要求 (10) 3.2存在问题 (13) 3.3现状评价 (13) 4绩效目标 (14) 4.1生态环境效益目标与指标 (14) 4.2投融资效率目标与指标 (15) 4.3管理效力目标与指标 (15) 4.4社会效应目标与指标 (19) 5技术路线与措施 (20) 5.1河道整治工程 (20) 5.2库区生态保护工程 (23) 5.3水环境修复工程 (24) 6效益分析 (30) 6.1社会效益 (30) 6.2经济效益 (30) 6.3生态环境效益 (31)
6.4管理效益 (31) 7保障措施 (32) 7.1.组织领导保障 (32) 7.2政策法规保障 (33) 7.3 资金投入保障 (34) 7.4 技术人才保障 (34) 8项目及投资估算 (35) 8.1投资估算 (35) 8.2实施期限 (38) 8.3运营保障措施 (38)
1概述 1.1项目背景 水是生命之源,水质是生态之本,水环境保护事关人民群众切身利益,事关我省全面建成小康社会,是推进生态文明、建设美丽河南的重要内容.河南省地跨淮河、黄河、海河和长江四大流域,承担着保护淮河源头和南水北调中线工程“一渠清水北送”的重任.当前,我省正处在全面建成小康社会的攻坚期、加快现代化建设的重要阶段,经济社会发展进入新常态,水环境保护工作面临前所未有的压力和挑战,部分区域水环境质量差、河道环境流量不足、水生态受损重且难以短期内恢复、水环境隐患多等问题日益凸显.为全面落实《国务院关于印发水污染防治行动计划的通知》(国发〔2015〕17号)以及《河南省人民政府关于印发河南省碧水工程行动计划(水污染防治工作方案)的通知》(豫政〔2015〕86号),切实改善...市水环境质量,确保水环境质量“只能更好、不能变坏”,并结合我市实际,特编写本实施方案. 1.1指导思想 以党的十八大和十八届三中全会精神为指导,以加快推进全国生态文明试点市建设为统领,以“三源两河一中心”(三源即南水北调中线工程水源、淮源、集中式饮用水源,两河即唐河、白河,一中心即市、县两级中心城区)为重点,以重点工程为支撑,深入开展水环境污染综合整治,完善长效监管机制,切实保障水环境安全,为打造大美...、活
疏浚施工方案
金山湾生态城基础设施项目 疏浚工程 疏浚施工专项方案（青荣铁路桥南侧） 批准： 审核： 编制： 中水电金山湾生态城基础设施项目总承包部
二〇一四年三月二十日
目录 1 编制依据.................................................................................... - 0 - 2 编制原则.................................................................................... - 0 - 3 工程概况.................................................................................... - 1 - 3.1 工程概述 ....................................................................... - 1 - 3.2 主要工程量 ................................................................... - 2 - 3.3 工程特点难点及措施 ................................................... - 2 - 4 施工组织.................................................................................... - 4 - 5 施工总平面布置 ....................................................................... - 5 - 6 工期计划.................................................................................... - 5 - 6.1 工期保证措施 ............................................................... - 5 - 7 资源配置计划 ........................................................................... - 6 - 7.1 设备配备 ....................................................................... - 6 - 7.2 施工人员配置 ............................................................... - 8 - 8 施工方案及技术措施 ............................................................... - 9 - 8.1 施工测量 ....................................................................... - 9 - 8.2 施工准备 ....................................................................... - 9 - 8.3 疏浚施工 ..................................................................... - 12 - 9 夜间施工措施 ......................................................................... - 18 - 10 质量、安全、环保措施 ....................................................... - 18 - 10.1 质量控制措施 ........................................................... - 18 - 10.2 安全保障措施 ........................................................... - 18 -
深圳市河道生态修复工程
深圳市河道生态修复工程 1深圳市特区内城市河道现状 深圳市特区内主要有深圳河、大沙河、福田河、布吉河、新洲河、深圳水库排洪河以及盐田河等。这些河在整治之前都是很明显的“直线型;三而光”少绿化单一型;河道。河道都是采用单一的型式(梯形或矩形)、单一的植物绿化，单一的浆砌石材料。整齐划一的河道断面、笔直的河道走向，固然是一种景观，但是它与现代人们追求的回归自然不相一致，与现代城市河道周边无论现代或占典的建筑艺术都极不相称，与周围环境也极不协调。无论块石还是混凝上都是坚硬、耐压的无机材料，上而不民一草一木，铺到哪里，哪里就是灰白色一片，缺乏生机，一旦这些结构老化破损，就形成河边建筑垃圾，环境景观受到影响。 1.1深圳市河道污染现状 由于人类的活动,深圳市河道污染日益严重,从污染源上看,深圳市河道污染主要包括点源污染、面源污染和内源污染;从污染物上看,主要包括有机污染和N、P等营养盐污染。深圳市河道水质恶化既是一个水污染问题,也是一个水生态失衡的问题。目前深圳市河道渠化改变了天然河道的地形地貌,使河道植被失去了赖以生存的基础,也不利于微生物附着和微型动物栖息繁殖、高等动物生存;河道形态、结构均质性使河道水流多样性消失;河道裁弯取直使河道水流加速,不利于各种生物栖息;而河底和岸坡硬化切断了水土营养交换,使河水成为孤立于土壤之外的系统,无法独立支撑复杂的水生生物群落。以上因素导致河道生境的恶化,生态链断裂、生态网格结构破碎、生物多样性消失,河道生态系统能量流动和物质循环规模降低,当有机污染和N、P等营养盐进入河道,超出河道自净能力时,就会导致河道生态链断裂,系统失衡甚至崩溃。 1.2深圳市河道治理现状 河道治理必须遵循自然生态规律,河道生态系统稳定性取决于其能量流动和物质循环规模是否在自然条件所允许的范围之内,而将过量的有机物和营养盐移出系统则是河道治理的根本着眼点。目前深圳河道治理水质改善工程采用的是河道曝气增氧、生物飘带、自然循环水处理、河道微生物投放等技术。深圳市河道经过近几年的强化治理,已基本完成了对河道有机污染的控制,打通河道生态系统碳循环的通道,但面源污染无法控制,内源污染依然存在,深圳市河道污染源将由点源污染为主转变为以面源污染和内源污染为主,河道污染物将由有机污染为主转变为以N、P等营养盐污染为主,河道治理策略必须由污染源控制、水质净化工程为主转变为以河道生态修复为核心,通过改造河道形态结构,调节河道水量和水流态,构建河道生物多样性,恢复河道洁净好氧生态系统,提高河道自净能力。经过10多年的综合整治,深圳市河道治理已经进入攻坚阶段。研究表明,目前深圳河道现状既是污染问题,更是生态失衡的问题,对特区河道进行生态修复势在必行。 2 深圳市河道治理技术 城市河道、湖泊等地表水系统与城市污水处理系统、城市地下水系统密小可分.城市河道生态修复小能只局限于河道本身.还必须考虑城市水污染控制.城市水资源循环再生等囚索。生态修复技术主要包括:（1）道水文条件的恢复。通过补水调水措施.使河道恢复适宜生物群落生长的水质、水量以及流态、水深等水文要素。（2）生物栖息地的恢复。通过适度人工干预和保护措施.恢复河流廊道的生境多样性。（3）生物群落多样性恢复。通过引入本土生物.优化河道生物群落结构.构建生物多样性.恢复河道自然良性生态系统的结构和功能。 2.1水污染控制技术 将城市污水处理系统和地表水系作为一个整体.通过截污措施控制河道点源污染.通过清淤减少河道内源污染。城市河道是一个开放系统.河道而源污染和大部分内源污染很难通过市政工程乎段进行控制.主要通过生物修复技术进行治理。应用于河道治理的生物修复技术包