xuzhihongqujiushizheyangyige“yudi”。zaiheliuliangan，renweixuanzeyixiediwadiqu、shidihubodeng，qizhongduoshuhaishilishishangjianghehongshuiyanmeihexuhongguodechangsuo。danghongshuichaobiao，jiuhuiqiyongxuzhihongqu，linshicunshui，jianqingzhongdianbaohuqu、dazhongchengshi、zhongyaoganxiandefanghongyali，jiangdihedaodehongfengliuliang，bimianhongshuifanlan。蓄(xu)滞(zhi)洪(hong)区(qu)就(jiu)是(shi)这(zhe)样(yang)一(yi)个(ge)“(“)余(yu)地(di)”(”)。(。)在(zai)河(he)流(liu)两(liang)岸(an)，(，)人(ren)为(wei)选(xuan)择(ze)一(yi)些(xie)低(di)洼(wa)地(di)区(qu)、(、)湿(shi)地(di)湖(hu)泊(bo)等(deng)，(，)其(qi)中(zhong)多(duo)数(shu)还(hai)是(shi)历(li)史(shi)上(shang)江(jiang)河(he)洪(hong)水(shui)淹(yan)没(mei)和(he)蓄(xu)洪(hong)过(guo)的(de)场(chang)所(suo)。(。)当(dang)洪(hong)水(shui)超(chao)标(biao)，(，)就(jiu)会(hui)启(qi)用(yong)蓄(xu)滞(zhi)洪(hong)区(qu)，(，)临(lin)时(shi)存(cun)水(shui)，(，)减(jian)轻(qing)重(zhong)点(dian)保(bao)护(hu)区(qu)、(、)大(da)中(zhong)城(cheng)市(shi)、(、)重(zhong)要(yao)干(gan)线(xian)的(de)防(fang)洪(hong)压(ya)力(li)，(，)降(jiang)低(di)河(he)道(dao)的(de)洪(hong)峰(feng)流(liu)量(liang)，(，)避(bi)免(mian)洪(hong)水(shui)泛(fan)滥(lan)。(。)