Lucas1-5暴雨控制措施過程

1、Watershed Modeling and Hydrologic ProcessesoPrecipitation- Rain & snow （降水雨雪）oInterception- Plant leaf storage （截留植物樹葉存儲）oSurface Runoff- Net of interception, not infiltrated（地表徑流不下滲的總截留量）oInfiltration- Net of interception, infiltrated（下滲下滲的總截留量）oInterflow (subsurface flow) shows as recession li

2、mb（壤中流，或潛流可視為退水分支）oEvapotranspiration (ET)- Most of infiltrated flow（蒸發(fā)蒸騰作用(ET)下滲流的大部分）oRecharge- Rest of Infiltrated after Interflow and ET（補給經(jīng)過壤中流和蒸騰后剩余的下滲部分）oGroundwater discharge-Base flow（排放形成的地下水水流）Source: VDEQ (2009) Virginias Water Resources, http:/ 降水下滲地表徑流蒸發(fā)蒸騰地下水水流地表徑流地下水水流河流蒸發(fā)降水壤中流不飽和區(qū)土壤水

3、（地下水）補給重力疏干地下水位Precipitation and Interception降水和截留作用Precipitation is the important factor affecting the amount and spatial distribution of water through a watershed降水是一個影響流域中的水空間數(shù)量分布的重要因素Interception is the process which may alter the pattern and the amount of water reaching the soil surface by the

4、vegetative cover截留作用可以改變水通過植被覆蓋到達土壤表面的模式和數(shù)量Factors affecting interception:影響截留的因素Type of land cover土地覆蓋類型Extent of land cover土地覆蓋程度Condition of land cover土地覆蓋條件Source: /wiki/Interception_(water) 降水樹干莖流穿透降雨樹冠截留下滲森林地面截留Infiltration下滲作用Rainfall reaches the ground surface fills dep

5、ressions, then enters the soil or runs off. 降雨到達地表填滿洼地，然后進入土壤或流走Infiltration is the process which rainfall enters the soil layer下滲就是降雨進入土層的過程Factors affecting infiltration:影響下滲的因素Soil Characteristics: Suction Head and Saturated Hydraulic Conductivity土壤特點：吸入水頭和飽和的水力傳導率Soil saturation: Suction Head土壤飽

6、和度：吸入水頭The amount and characteristics of precipitation: intensity and depth降水量和降水特點：強度和雨量Land cover: vegetated vs. bare土地覆蓋：植被 vs. 裸露Slope of the land: Less important 土地坡度：相對次要Source: http:/ 降雨下滲滲漏非飽和帶地下水位Surface Runoff地表徑流Surface Runoff is the rainfall reaching ground surface that does not infiltra

7、te.地表徑流是降雨到達地表且不下滲的部分Factors affecting runoff:影響徑流的因素：Soil Characteristics: Suction Head and Saturated Hydraulic Conductivity. 土壤特點：吸入水頭和飽和的水力傳導率。Rainfall characteristics: intensity, duration.降雨特點：強度，持續(xù)時間。Vegetation: Rooting density, roughness植被：根密度，粗糙度。Watershed characteristics: overland flow type,

8、 length and slope.流域特點：地面水流類型，長度和傾斜度。Attenuating features: depression storage, reservoir storage.衰減特征：洼地存儲，蓄水池存儲。Evapotranspiration蒸發(fā)蒸騰作用Evapotranspiration is the process of evaporation from soils and transpiration through leaves. 蒸發(fā)蒸騰是通過土壤蒸發(fā)和樹葉蒸騰的過程。Factors affecting Evapotranspiration:影響蒸發(fā)蒸騰的因素：En

9、ergy availability 能量可用性Vapor pressure 蒸汽壓Wind speed 風速Water availability 水可用性Vegetative cover 植被覆蓋Plant type and height 植物類型和高度Soil characteristics such as heat capacity, soil chemistry, and albedo土壤特點如比熱容，土壤化學性質(zhì)和反射率Source: /wiki/Evapotranspiration.蒸發(fā)蒸騰=蒸騰+蒸發(fā)蒸騰草地樹蒸發(fā)徑流地下水補給Soil

10、Moisture Storage土壤降雨貯水量Soil moisture storage is the amount of water stored in the soil within the plants root zone土壤降雨貯水量是土壤中植物根部區(qū)域的存水量Factors affecting soil moisture storage:影響土壤降雨貯水量的因素：Soil texture土壤結(jié)構(gòu)Crop rooting depth作物扎根深度Water Balance in soil can be similar to reservoir storage土壤中的水平衡可以類比于儲水池

11、貯水量Infiltration increases moisture下滲提高濕度Evapotranspiration removes moisture upward蒸發(fā)蒸騰向上帶走濕度Interflow removes moisture laterally壤中流橫向帶走濕度Drainage to groundwater removes moisture downward排放進入地下水向下帶走濕度Source: Allen, R.G., Pereira, L.S., Raes, D., and Smith, M. (1998) Crop Evapotranspiration: Guideline

12、s for Computing Crop Water Requirements. United Nations Food and Agricultural Organization (FAO), Irrigation and Drainage Paper 56, Rome, Italy. 蒸發(fā)蒸騰雨灌溉徑流毛細上升深層滲透飽和田間保水量閾值萎蔫點虧水Groundwater地下水Groundwater is the permanently saturated zone under the vadose zone. 地下水是處于包氣帶下面的永久飽和帶Recharged from vadose zo

13、ne as net infiltration after evapotranspiration and interflow補給來自包氣帶的經(jīng)過蒸發(fā)蒸騰和壤中流之后的下滲總量Discharges as base flow into streams, maintaining flow between events. 隨著水流進入河流排放，保持著兩者之間的水流。Factors affecting groundwater flow movement:影響地下水流動的因素：Topography地形學Subsoil/Bedrock characteristics 下層土/基巖特點Riparian zone

14、 evapotranspiration河岸地區(qū)的蒸發(fā)蒸騰Source: USGS - GROUND WATER ATLAS of the UNITED STATES: Delaware, Maryland, New Jersey,North Carolina, Pennsylvania, Virginia, West Virginia, HA 730-L 包氣帶飽和帶毛細上升區(qū)水位地下水流動Water Budget水量平衡The relationship between input and output of water through a region.一個地區(qū)水量輸入與輸出的關(guān)系。Requ

15、ires estimating the amount of water in each component.要求預測在每一個部分的水量。Requires calculating movement of water through different components.要求計算每一個部分之間的水流動。Key components of water budget:水平衡的關(guān)鍵部分Precipitation 降水Surface-Runoff 地表徑流Evapotranspiration 蒸發(fā)蒸騰Groundwater flow 地下水水流Change in surface-water and g

16、roundwater storage 地表水與地下水貯水的交換Change in snow and ice storage 冰貯水和雪的交換Human withdrawals 人類開采Source: /watercensus/water-budgets.html Water Budget水量平衡Surface Water Budgets:地表水平衡：o Streamflow R= SRO+SSF+B河流量 R=SRO+SSF+Bo Evapotranspiration ET = E+I+T蒸發(fā)蒸騰 ET=E+I+To Precipitation P=ET

17、+R降水 P=ET+R Where:Stream Flow (R), Surface Runoff (SR0), Subsurface flow or interflow (SSF), Base Flow (B), Evapotranspiration (ET), Evaporation (E), Transpiration (T), Interception (I), Precipitation(P). 其中：河流流量(R)，地表徑流(SRO)，地下徑流流或壤中流(SSF)，基流(B)，蒸發(fā)蒸騰(ET)，蒸發(fā)(E)，蒸騰(T)，截留(I)，降水(P)。Infiltration- Mechan

18、isms下滲機制Effects of Vegetation (Ralston, 2004, Rachman et al 2004). 植被作用（羅爾斯頓，2004，拉赫曼等人，2004）Vegetation restores/enhances infiltration rates. Up to several orders of magnitude higher. 植被恢復/ 提高下滲速率?？商岣邘讉€量級。Roots penetrate confining layers, open up soil structure. Root turnover forms macropores.根穿透隔水層

19、，打開土壤結(jié)構(gòu)。根翻過來形成大孔隙。Native grasses in crops infiltrate an order of magnitude higher than adjacent cropped area. 作物中天然草地的下滲比周邊作物區(qū)下滲大一個量級。Even in deposition setting, infiltration outside the grasses were half that of crops. 即使在沉積作用的設定下，草地以外的作物的下滲是草地的一半。Effects of Organic Matter (Saxton and Rawls, 2004).

20、 有機物質(zhì)的作用（薩克斯頓和羅爾斯，2004）。Organic matter (OM) content substantially increases infiltration rates.有機物質(zhì)(OM)含量極大地提高下滲速率Primarily due to decreased bulk density. Soils high in OM cannot be compacted 主要因為體密度的降低。高有機物質(zhì)含量的土壤無法有緊密的狀態(tài)Intact mineral topsoil typically 1-2% OM, but substantially less if disturbed.

21、完整的礦物表土一般含有1-2%有機物質(zhì)，但一旦被擾亂，會極大的降低。Soils can be amended to an OM content of 5-10% (w/w).土地可以修復成含有5-10%(重量/重量)的有機物質(zhì)含量。OM increases field capacity in sandy soils by approximately 10%.有機物質(zhì)提高場地約10%的砂土能力含量。OM also promotes the microbial community, contributing to soil aggregate formation. 有機物質(zhì)也可以增進微生物群落，為

22、土壤聚集形成做貢獻。Infiltration- Mechanisms下滲機制Effects of Compaction (Pitt 1987, OCSCD, 2001, Saxton and Rawls, 2004). 緊密結(jié)構(gòu)的作用（皮特 1987，海洋郡水土保護區(qū)，2001，薩克斯頓和羅爾斯，2004）Compaction can substantially reduce infiltration rates.緊密結(jié)構(gòu)可以極大地減少下滲速率。Especially in sandy soils, where rates have been shown to decline from HSG

23、“A” to “D”.特別是在砂土中，速率被證明可以從HSG的A降到DThis is primarily due to increased bulk density. 這主要是因為體密度的提高。Compaction greatly inhibits the growth of plants, since roots cannot extend through the soil.緊密結(jié)構(gòu)大大地抑制了植物的生長，由于根不能伸展穿透土壤。Compaction not alleviated by freeze/thaw cycles- Roman wheel tracks still visible

24、in England.結(jié)冰/解凍循環(huán)不會減輕緊密結(jié)構(gòu)羅馬輪距在英格蘭依然可見Pedotransfer Functions (PTFs) (Saxton and Rawls, 2004) . 土壤傳遞函數(shù)(PRFs)（薩克斯頓和羅爾斯，2004）。Compaction and OM greatly affect the underlying textural class properties of the mineral soils.緊密結(jié)構(gòu)和有機物質(zhì)極大地影響無機土壤的基本結(jié)構(gòu)類型特點PTF equations predict saturated hydraulic conductivity

25、(Ksat), suction wetting head (), field capacity, and wilting point.土壤傳遞函數(shù)(PTF)等式預測飽和水力傳導率，吸入水頭，土壤毛細含水量，和萎蔫點。The SPAW model at Saxtons web site recommended to be used to obtain Ksat. 推薦使用在薩克斯頓網(wǎng)站上的SPAW模型來獲得Ksat值。SPAW provides conservative results without having to use a safety factor (typically 2).SPA

26、W模型能在非必須使用安全因子的情況下提供保守的結(jié)果(類型2)Soil Properties- SPAW Model Guidance土壤特點SPAW模型指導SPAW used to estimate saturated and unsaturated hydraulic conductivities as function of soil properties and moisture. Very useful for model parameters. SPAW曾用來預估飽和與不飽和水力傳導率，將其作為土壤特點和濕度的函數(shù)。這些是非常有用的模型參數(shù)。Infiltration Computat

27、ions下滲計算)()(1)(0tFhKtfsatIn the Green-Ampt (G-A) formulation, infiltration rate is computed as follows: 在格林安姆特方程式中，下滲速率的計算如下：where F(t) is volume infiltrated t, Ksat is saturated hydraulic conductivity, h0 is the ponding depth, is the capillary suction head at the wetting front, and is initial moist

28、ure deficit. 其中F(t)是下滲體積t, Ksat是飽和水力傳導率，h0是積水深度，是在濕潤界面的毛細吸入水頭，是初始濕度差。G-A accurate for each location for Ksat and , but pervious areas have very wide range of values.格林安姆特對于每一個地點的Ksat和都是準確的，但透水區(qū)域的值范圍非常廣。So runoff flows from areas with low Ksat and to areas with higher Ksat and 所以各區(qū)域的徑流會從Ksat和的低值區(qū)流向Ks

29、at和的高值區(qū)。As a result, infiltration rates actually increase as rainfall intensity increases. 結(jié)果是，由于降水強度的提高，下滲速率實際上提高了。This is what the Curve Number (CN) method simuates as an exponential distribution of infiltration parameters over space subjected to an exponential distribution of rainfall over time (

30、Yu, 1998). 這是曲線數(shù)(CN)法模擬下滲參數(shù)在空間上的一個指數(shù)分布的結(jié)果。這個分布受制于降雨在時間上的指數(shù)分布。(Yu,1998)Most common method in USA used for designing flood control facilities. 在美國用來設計洪水控制的最普遍方式是控制市政管線。Curve Number Hydrology曲線數(shù)水文Based upon observations of thousands of events in mostly rural watersheds, Victor Mockus generated the foll

31、owing equation:基于對數(shù)以千計大多數(shù)發(fā)生在鄉(xiāng)間流域事件的觀測，維克多莫卡斯發(fā)明了以下等式：Where Q is runoff in 24 hour event, P is precipitation depth, S is storage depth (the amount that infiltrates over 24 hours) and Initial abstraction Ia (the amount that doesnt runoff) is 20% of S. 其中Q是24小時事件徑流，P是降雨量，S是貯水量（超出24小時的下滲量）和初損量Ia（沒有流走的量）是

32、S的20%。Note that Ia (initial abstraction) is a large proportion of small events. Should be lower. 注意Ia（初損量）占小事件很大的一部分。應該稍微降低。The following equation relates S to Curve Number (CN):通過以下等式將S與曲線數(shù)(CN)聯(lián)系起來：The higher the CN, the lower S, and Ia will be.CN越大，S越小，Ia也越小。SPIPQa8 . 0)(2101000CNSCurve Number Hyd

33、rology曲線數(shù)水文(Pitt, 1987)Due to Ia being too big in small events, “effective” CN in small events has to increase. 由于Ia在小事件中比例太大，必須增大小事件中的“有效”的曲線數(shù)。Current thinking is that Ia should be closer to 5% of S, not 20%. 現(xiàn)行的想法是Ia應該更接近S的5%，而不是20%。Ia is really the suction term in the Green-Ampt equation, not dep

34、ression storage.Ia是格林安姆特等式中真正的吸入量，而不是洼地貯水量。LID HydrologyLID 水文RAINFALL- RUNOFF RESPONSE- OBSERVED, DURMM & TR-20 025500255075100125RAINFALL (mm)RUNOFF (mm)PerviousC/DDURMM 73.5TR-20 73.5Urban SoilsDURMM 67.5TR-20 67.5Pervious BDURMM 59.0TR-20 59.02.0 INCHQUALITYEVENT3.3 INCHBANKFULLEVENT(Lucas,

35、2004)（盧卡斯，2004） Pitt (1987) developed response for disturbed urban soils confirmed by observations. 皮特（1987）為受擾城市土壤開發(fā)出了受觀測限制的曲線。 Pitt equations used in DURMM model for Delaware in USA (Lucas, 2004). 皮特等式在美國DURMM模型中被用于特拉華州。 This allowed use of extensive NRCS CN dataset for small storm responses. 這使得大

36、規(guī)模地運用國家自然保護服務的CN數(shù)據(jù)集作用于小型暴雨曲線得到了允許。LID HydrologyLID 水文Remember, it is runoff captured that is what really matters, not precipitation falling. 記住，起到作用的是徑流收集而不是降水下落。Percentage of runoff is function of mix between impervious and pervious, and pervious CN.徑流的百分比是不透水率和透水率混合與透水CN之間的函數(shù)。Table shows 50% pervi

37、ous at CN of 61, like tower project with landscaping. 表格顯示了在61CN處有50%透水率，比如景觀美化的塔工程。If all rainfall up to 30mm (1.18 inch) intercepted, represents capturing 80% of annual runoff.如果截留的降雨達到30毫米(1.18英寸)，代表收集了80%的徑流。If all rainfall up to 51mm (2.00 inch) intercepted, represents capturing 93% of annual r

38、unoff.如果截留的降雨達到51毫米(2.00英寸)，代表收集了93%的徑流。As impervious increases, capture percentage goes down. 隨著不透水率的增加，收集的百分比降低。INFILTRATION 下滲:Positively affected by high organic matter, low compaction, and presence of plants.正比于高含量的有機物質(zhì)，低緊密性，和植物存在度。Methods to improve these factors can have very large effect on

39、infiltration rates. 提高這些因素的方法可以極大地作用于下滲速率。HYDROLOGY 水文:Runoff from disturbed pervious soils often much higher than CN method predicts. 來自受擾透水土壤的徑流常常比CN法預測的更多。Runoff from small events dominated by impervious cover. 來自小事件的徑流主要由不透水覆蓋面控制。Typical application of composite CN method not appropriate for LID

40、 hydrology.綜合CN法的典型應用并不適合LID水文。Must segregate connected impervious from disconnected impervious. 必須把連接的不透水區(qū)和分散的不透水區(qū)分離開。Must use design storm (DS) that is more representative than flood storm. 必須使用暴雨設計(DS)，比暴雨洪水更有代表性。LID HydrologyLID 水文LID ModelingLID 模型All approaches intend pre-development hydrology

41、 to be replicated by the provision of BMPs.所有想要通過BMPs的提供復制開放前水文的方式。Rational Method is useless, since does not route or attenuate by detention or infiltration.推算方式是沒有作用的，因為它不能演算，也不能被滯留或者下滲衰減。Specific discharge rate oversimplifies, since same even though soils and vegetation very different. 特定排放速率過度簡化

42、，因為即使是同樣的土壤和植被，下滲速率還是很不一樣的。Specific detention volume is also inadequate for same reasons. But useful for initial screening. 同樣的理由，特定的滯留量也是不夠的。但對于初步篩選還是有用的。Must use routing approach so BMPs determined by initial screening meet discharge criteria.必須使用演算的方法，因此經(jīng)由初步篩選決定的BMPs可以達到排放標準。The CN approach is us

43、ed nationally throughout USA for both for screening and for routing. CN法在整個美國范圍內(nèi)被用于篩選和演算。It is the basis for many models such as TR-20, HEC-1. We discuss TR-20 (simplified as TR-55).它也是很多模型如TR20，HEC1的基礎。我們討論一下TR20（簡化成TR55）。LID ModelingLID 模型For initial screening, can use the overall composite CN app

44、roach. 對于初期篩選，可以使用總體綜合CN法。Volume required is difference in runoff depths from pre-development to post-development. 要求的體積在不同徑流量中從開發(fā)前到開發(fā)后都是不同的。Multiplied by area, this gives total volume required. 乘上面積，這可以算出要求的總體積。BMPs then computed according to volume provided in surface storage and in media/stone vo

45、ids. BMPs之后可以依據(jù)在地表貯存提供的體積和媒介/石頭間的縫隙計算。For detailed design, segregate various types of source areas to determine contribution of each. 對于詳細的設計，分離不同類型的源頭區(qū)域來決定每一樣對設計的貢獻。Segregate directly connected effective impervious area (EIA), since generates runoff every event.分離直接連接的有效不透水區(qū)域(EIA)，因為每一項都會產(chǎn)生徑流。Compo

46、site disconnected impervious areas (DIA) and adjacent pervious to generate their runoff . 綜合分離的不透水區(qū)域(DIA)和鄰近的透水面來生成他們的徑流。Natural pervious areas will generate very little runoff at all.天然透水區(qū)域會幾乎不產(chǎn)生徑流。Multiply source areas by their depths to get loads. 將源頭面積乘上他們的深度可以得到載量。LID ModelingLID 模型Design Storm

47、 (DS) Summary 暴雨設計(DS)方式?Design storms (DS) are very common way to design hydraulic structures. 暴雨設計(DS)是非常普遍的設計水力結(jié)構(gòu)的方式。Average recurrence interval (ARI, or frequency) depths are based on long term rainfall records. 平均重復周期(ARI,或頻率)深度是基于長期降雨記錄的。DS synthetic hyetographs often accentuate peak flows sin

48、ce directed toward flooding. 暴雨設計(DS)合成雨量圖常常會削弱水流峰值因為將其直接導向洪水。So design storms may not represent any actual events, but useful for initial design. 所以暴雨設計一般不會代表任何真實事件，但對初期設計很有用。DS models can rapidly audit capacity and performance, and optimize design.暴雨設計(DS)模型可以快速的審查設計的能力和性能并優(yōu)化設計。TR-20 is most used

49、model in USA, based on CN methods. Here used with HydroCAD.TR-20是在美國最常用的基于CN方法的模型。這里講其與HydroCAD一起使用。While DS models are very useful, more information is needed to evaluate SCMs. 當暴雨設計(DS)模型非常有用時，需要更多信息來評估雨水管理措施。Continuous Simulation vs. Design Storm連續(xù)性模擬 vs. 暴雨設計Design storms (DS) do not represent a

50、ny actual events, so useful only for initial design. 暴雨設計(DS)并不代表任何真實事件，所以只適用于初期設計。Continuous simulation (CS) simulates response using long term rainfall and flow records. 連續(xù)性模擬(CS)可將長期降雨和水流記錄用于模擬結(jié)果。Flow Duration Curve (FDC) is much better indicator of performance than a DS analysis流量歷時曲線(FDC)是比暴雨設計

51、(DS)分析更好的性能指標The FDC compares the duration of flows of differing magnitudes, so all events represented. 把流量歷時曲線與不同量級水流的持續(xù)時間作比較，因此可以代表所有事件。The FDC is the fundamental metric of how well LID SCMs work.流量歷時曲線是LID雨水控制措施有效程度的基本度量。CS data can also define DS depth. If enough data available, DS hyetograph al

52、so derived. 連續(xù)性模擬可以定義暴雨設計深度。如果有足夠的可用數(shù)據(jù)，暴雨設計雨量圖也可以推導得出。CS Models-SWMMEPA SWMM is very comprehensive CS model. SWMM now includes useful modules for LID BMPs so they can be modeled quite well. SWMM also includes aquifers, which can mimic overland flow hydrology quite well Details of SWMM operation and

53、examples are focus of the afternoon session. First, must address how both DS and CS models should address vertical and lateral flow in layered systems. This element is critical in modeling LID BMPs, and often overlooked. Following section presents how flows in layered systems such as bioretention ar

54、e modeled. Flow Duration Curve comparison between Urban and Forest Streams. 城市和森林河流的流量歷時曲線比較Urbanization greatly increases both discharge and duration of erosive flows over bankfull. 城市化極大地增加了超出滿槽流的水流排放和侵蝕流的維持。Due to logarithmic scale, these differences are even greater actual magnitude. 由于是在對數(shù)尺度下，這

55、些差別會變得比實際量級更大。Urban Stream城市溪流Forest Stream森林溪流Discharge Increases 10 x排放提高10倍Flow Duration Increases 10 x水流持續(xù)時間10倍“Normal” Flow Rate“正?！绷魉貰ankfull Flow Rate滿槽流速Base Flow Decreases 基礎流量減少Continuous Simulation 連續(xù)性模擬流量歷時曲線Why FDCs?- Physical and Chemical為什么用流量歷時曲線(FDCs)？物理的和化學的(原因)Impervious FDC impli

56、cations for Flooding :All runoff events have much higher flows compared to natural.So many more bankfull flow events (from 10/yr).Such “flashy” streams result in frequent nuisance flooding. Impervious FDC implications for Bank Stability:Resultant higher bankfull flow vastly increases erosive energy.

57、So bank erosion, downcutting and channel incision accelerated.Resulting erosion major source of sediments in streams.Impervious FDC implications for Base Flow:Decreased base flow due to diversion to runoff.Base flow temperatures higher, and dissolved oxygen lower.不透水流量歷時曲線(FDC)對洪澇的含義 :所有徑流事件都有比天然徑流高

58、得多的流量所以有更多的漫灌流事件（從少于1次每年到多余10次每年）。比如“瞬間的”潮流導致頻繁的洪澇災害。不透水流量歷時曲線(FDC)對河岸穩(wěn)定性的含義:因此產(chǎn)生的更多的漫灌流極大地提高了侵蝕能量。所以河岸侵蝕，向下侵蝕和河道切削加速。導致侵蝕河流中沉積物的主要源頭。不透水流量歷時曲線(FDC)對基流的含義:由于徑流分散從而減低基流.基流溫度更高，溶解的氧氣更少。Why FDCs?- Biological為什么用流量歷時曲線(FDCs)？生物的（原因）Impervious FDC effects upon Benthic Macroinvertebrates:Increased flow di

59、srupts breeding cycles and feeding.Increased flow eliminates many individuals.Sediments smother breeding and refuge sites.Floods wash away woody debris habitat. Loss of habitat eliminates many species.Impervious FDC effects upon Fish:Most macroinvertebrate food sources eliminated.Increased flow disr

60、upts breeding cycles and feeding.Sediments smother breeding and refuge sites.Floods wash away woody debris habitat. Low flow conditions elevate temperature and reduce oxygen.Loss of habitat eliminates many species.不透水流量歷時曲線(FDC)對海底大型無脊椎動物的影響:提高的水流擾亂繁殖周期和覓食。提高的水流消除許多的個體。沉積物抑制繁殖和避難場所。洪水沖刷掉棲息地的木質(zhì)碎屑。 棲息地的失去會消除許