沙(sha)溪是閩江(jiang)的主(zhu)流(liu)(liu)(liu),發源(yuan)于武(wu)夷山脈杉嶺(ling)南麓的九(jiu)縣山,屬建寧縣均口(kou)(kou)(kou)鄉;源(yuan)頭為水(shui)(shui)(shui)茜溪,流(liu)(liu)(liu)經漁潭至(zhi)寧化(hua)稱(cheng)東溪,在(zai)寧化(hua)縣城下游匯入(ru)武(wu)義溪后(hou)稱(cheng)九(jiu)龍(long)溪,向東流(liu)(liu)(liu)向清流(liu)(liu)(liu),寧化(hua)境(jing)內合水(shui)(shui)(shui)口(kou)(kou)(kou)以下又稱(cheng)翠江(jiang)。清流(liu)(liu)(liu)境(jing)內一段(duan)(duan)又稱(cheng)龍(long)津河。九(jiu)龍(long)溪流(liu)(liu)(liu)至(zhi)永安西郊10公里(li)處有(you)文川溪匯入(ru),兩(liang)條(tiao)溪流(liu)(liu)(liu)猶(you)如(ru)燕尾,合流(liu)(liu)(liu)過后(hou)河段(duan)(duan)猶(you)如(ru)燕身,永安東郊一段(duan)(duan)猶(you)如(ru)燕頭,故這段(duan)(duan)5公里(li)溪流(liu)(liu)(liu)又稱(cheng)燕江(jiang)。永安至(zhi)沙(sha)溪口(kou)(kou)(kou)稱(cheng)沙(sha)溪,沙(sha)溪流(liu)(liu)(liu)經寧化(hua)、清流(liu)(liu)(liu)、明(ming)溪、永安、三(san)明(ming)、沙(sha)縣等六個縣市,在(zai)沙(sha)溪口(kou)(kou)(kou)與(yu)富屯溪匯合后(hou)注入(ru)閩江(jiang),此處建有(you)沙(sha)溪口(kou)(kou)(kou)水(shui)(shui)(shui)電站。
沙溪全(quan)長328公(gong)(gong)里,集水(shui)(shui)(shui)(shui)(shui)(shui)面(mian)積11793平(ping)方公(gong)(gong)里,占閩(min)江流域總(zong)面(mian)積19.33%,全(quan)年不(bu)(bu)會發生河(he)(he)干(gan)、斷流和冰封現象。降雨期(qi)(qi)集中(zhong)在(zai)4月(yue)(yue)至(zhi)8月(yue)(yue),水(shui)(shui)(shui)(shui)(shui)(shui)位暴(bao)漲暴(bao)落,洪峰持續(xu)期(qi)(qi)短,枯水(shui)(shui)(shui)(shui)(shui)(shui)期(qi)(qi)長(9月(yue)(yue)至(zhi)翌年3月(yue)(yue))。1955~1984年,沙縣(xian)石(shi)(shi)(shi)(shi)橋(qiao)水(shui)(shui)(shui)(shui)(shui)(shui)文站最(zui)(zui)高水(shui)(shui)(shui)(shui)(shui)(shui)位為(wei)(wei)羅星塔零點基(ji)面(mian)以上112.95米(mi)(mi),最(zui)(zui)低水(shui)(shui)(shui)(shui)(shui)(shui)位為(wei)(wei)103.70米(mi)(mi),平(ping)均水(shui)(shui)(shui)(shui)(shui)(shui)位為(wei)(wei)104.58米(mi)(mi)。沙溪航(hang)(hang)道(dao),河(he)(he)床(chuang)多是河(he)(he)谷型盆地和河(he)(he)曲型河(he)(he)谷相(xiang)間(jian),河(he)(he)床(chuang)質為(wei)(wei)巖石(shi)(shi)(shi)(shi)和沙卵(luan)石(shi)(shi)(shi)(shi),河(he)(he)寬(kuan)寬(kuan)窄相(xiang)間(jian),水(shui)(shui)(shui)(shui)(shui)(shui)深深淺不(bu)(bu)一,很多河(he)(he)段(duan)(duan)巖盤連片,礁石(shi)(shi)(shi)(shi)棋布,險灘多,水(shui)(shui)(shui)(shui)(shui)(shui)流湍急(ji),流態紊亂,而沙卵(luan)石(shi)(shi)(shi)(shi)淺灘多的(de)(de)河(he)(he)段(duan)(duan)又長,一般水(shui)(shui)(shui)(shui)(shui)(shui)深只有0.3~0.8米(mi)(mi)。沙溪通(tong)航(hang)(hang)里程,從(cong)寧化(hua)縣(xian)的(de)(de)禾口起至(zhi)南(nan)平(ping),全(quan)長324.4公(gong)(gong)里,1965年寧化(hua)縣(xian)境內的(de)(de)橫鎖以上修建了水(shui)(shui)(shui)(shui)(shui)(shui)利閘壩,使40公(gong)(gong)里河(he)(he)段(duan)(duan)不(bu)(bu)能通(tong)航(hang)(hang),通(tong)航(hang)(hang)里程橫鎖至(zhi)南(nan)平(ping)為(wei)(wei)276.2公(gong)(gong)里。
沙(sha)(sha)溪(xi)流(liu)域從1993年開(kai)(kai)始,三明市大力開(kai)(kai)展沙(sha)(sha)溪(xi)河航電(dian)(dian)綜(zong)合開(kai)(kai)發項目,至2004年,共有永(yong)(yong)安安砂電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、永(yong)(yong)安豐海電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、永(yong)(yong)安鴨(ya)姆潭(tan)電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、永(yong)(yong)安西門電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、永(yong)(yong)安貢川(chuan)電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、三元竹洲電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、三元臺江電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、梅列斑竹電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、沙(sha)(sha)縣(xian)(xian)城關電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、沙(sha)(sha)縣(xian)(xian)高砂電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)、沙(sha)(sha)縣(xian)(xian)官蟹電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)11個梯(ti)(ti)級電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)。沙(sha)(sha)溪(xi)河梯(ti)(ti)級電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)總裝機容量(liang)11處/46.71萬(wan)千(qian)瓦,其中:已建成(cheng)電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)8處/37.71萬(wan)千(qian)瓦,在建電(dian)(dian)站(zhan)(zhan)(zhan)(zhan)(zhan)(zhan)3處/9萬(wan)千(qian)瓦。
不亞于珠江(jiang)夜景,尤其是三明的部分。