以永定河北京段为例，建立水文学和水力学相结合的水流演进模型，利用生态补水实测监测数据率定并验 证模型。利用建立的模型研究永定河北京段的生态补水规律及模式，结果表明：在持续稳定流量补水条件下，固 安（出境断面）通水后 11d 左右达到稳定状态，停止放水后可维持河道 12~13d 有水；在持续稳定流量下，随着补水 流量的增大，河道首次贯通的时间和损失水量占比均降低，且降低速率逐渐减缓，官厅补水下泄流量以 30~35 m3/s 为宜；在生态补水总水量受限条件下，先以大流量下泄再调整为小流量的补水方式，对快速实现全线通水、河道渗 漏回补地下水等效果更佳；平原段同步加入再生水和南水北调水，将进一步缩短全线通水时间；在官厅水库和平 原段再生水、南水北调水向河道补水 2.24 亿~4.14 亿 m3条件下，全线通水时间约需要 15d，固安断面出境水量约 1.05 亿~2.22 亿 m3，蒸发和渗漏水量 1.19 亿~1.93 亿 m3，且补水水量越大，下渗和蒸发水量的占比越低；卢沟桥-六 环路河段的入渗能力最强。本研究对永定河北京段生态补水水量、下泄过程及补水方式的确定具有实践意义。

Ecological ?water ?replenishment ?(EWR) ?is ?an ?important ?way ?for ?river ?and ?lake ?recovery, ?ecological restoration, ?and ?river ?function ?maintenance. ?Attempts ?have ?been ?made ?to ?replenish ?ecological ?water, ?such ?as transfering?water?from?the?Yellow?River?to?the?Yongding?River?(YDR)?and?transfering?water?from?the?Yangtze River?to?the?Hutuo?River.?However,?in?the?arid?area?of?northern?China,?the?river?has?water?only?for?a?limited?time. The?runoff?characteristics?in?the?process?of?EWR?have?great?uncertainty.?Therefore,?it?is?important?to?study?the?EWR law?and?water?discharge?mode?under?the?limited?ecological?water?supply. ??????A?one-dimensional?flow?evolution?model?based?on?the?Muskingum?method?and?the?Saint-Venant?equation?group was?established?by?taking?Beijing?section?of?the?YDR?as?an?example.?The?impact?of?complex?terrain?conditions could?be?avoided?in?the?modeling?of?the?mountain?gorge?section,?and?the?flow?process?changes?caused?by?the?river channel?characteristics?in?the?plain?section?could?be?fully?reflected.?The?measured?EWR?monitoring?data?were?used to?calibrate?and?verify?the?model?to?accurately?reflect?the?flow?change?and?the?water?quantity?balance. ??????The?results?show?that:?(1)?Under?the?mode?of?continuous?and?stable?flow?replenishment,?the?water?supply?in Gu'an?(exit?section)?reaches?a?stable?state?in?about?11?d,?and?may?continue?to?maintain?water?for?about?12-13?d?after the?water?discharge?was?stopped.?(2)?With?the?increase?of?the?flow?rate,?the?duration?of?the?river?with?water?and?the proportion?of?water?loss?decreased,?and?the?rate?of?decrease?gradually?slow?down.?The?optimal?EWR?flow?was?30-35 m3/s.?(3)?The?total?amount?of?EWR?was?limited,?and?water?release?with?a?large?flow?first?was?more?advantageous?in terms?of?the?whole?line?water?supply?time?and?groundwater?leakage?effect.?(4)?Adding?reclaimed?water?and?water from?South-to-North?Water?Transfers?Project?(SNWTP)?in?the?plain?section?may?further?shorten?the?water?supply time.?(5)?Assessing?the?ecological?water?supply?capacity?of?the?Guanting?Reservoir,?reclaimed?water,?and?water?from SNWTP,?the?designed?water?supply?is?in?the?range?of?2.24×108-4.14×108m3.?The?whole?line?of?the?Beijing?section?of the?YDR?will?be?open?to?water?for?about?15?d,?with?an?outflow?of?1.05×108-2.22×108m3,?groundwater?recharge,?and evaporation?of?1.19×108-1.93×108m3.?The?larger?the?amount?of?EWR?water,?the?lower?the?proportion?of?infiltration and?evaporation?water.?The?Lugouqiao?-?Liuhuanlu?section?had?the?strongest?infiltration?capacity. ??????This ?study ?has ?practical ?significance ?for ?the ?determination ?of ?EWR ?quantity, ?discharge ?process, ?and ?water discharge?mode?of?Beijing?section?of?the?YDR.?The?ENS?of?simulated?and?measured?data?suggests?that?the?model?can accurately?reflect?the?flow?change?and?the?water?quantity?balance.?It?shows?that?with?the?increase?of?the?flow,?the water?supply?time?and?the?proportion?of?water?loss?decrease,?and?the?optimal?flow?range?of?Guanting?Reservoir?is?30- 35?m3/s.?The?water?supply?mode?of?first?discharging?a?large?flow?and?then?stabilizing?to?a?small?flow?has?the advantages?of?fast?water?flow,?large?amount?of?groundwater?recharge,?and?simple?gate?control,?which?is?a?suitable discharge?mode?for?the?EWR?in?river?courses.