【摘要】：研究濱海地區(qū)海岸帶含水層中的海水地下水相互交換作用,包括海底地下水排泄、地下水動(dòng)態(tài)和溶質(zhì)運(yùn)移等,對(duì)評(píng)價(jià)濱海地區(qū)的地下水資源、正確區(qū)分近岸海域營(yíng)養(yǎng)物質(zhì)的來(lái)源以及改善海產(chǎn)養(yǎng)殖模式,具有重要的理論和實(shí)踐意義。以往的海岸帶海水地下水相互交換研究主要集中于沙質(zhì)、礫石海灘,而對(duì)于在國(guó)內(nèi)外濱海地區(qū)都廣泛分布的泥質(zhì)潮灘的研究卻比較少。本文選取了萊州灣東岸某一典型泥質(zhì)潮灘剖面作為實(shí)驗(yàn)場(chǎng)地,對(duì)該場(chǎng)地以前野外觀測(cè)所用的單井進(jìn)行改進(jìn),采用布設(shè)“對(duì)井”觀測(cè)井的方法,估算了在考慮滲出面以及密度影響下海水地下水的交換量。本文研究的潮灘剖面長(zhǎng)約450m,坡度1.8‰,沿垂直海岸方向均勻布設(shè)6口對(duì)井來(lái)觀測(cè)地下水動(dòng)態(tài),從內(nèi)陸向海向分別編號(hào)為W1、W2、W3、W4、W5、W6,每口對(duì)井在不同深度上安裝兩個(gè)LTC-Diver,每小時(shí)記錄一次水壓、溫度及電導(dǎo)率,監(jiān)測(cè)時(shí)間為2013年8月22日00:00到2013年9月21日00:00,共計(jì)720小時(shí)。同時(shí)還利用原位多徑降水頭法測(cè)量了每口井處沉積物的垂向滲透系數(shù),滲透系數(shù)變化范圍從4.06×10-6 ms-1到7.30×10-5 ms-1,其中W4滲透系數(shù)最大,W1滲透系數(shù)最小。每口觀測(cè)井中上下Diver的平均鹽度變化范圍從14.2gL-1到24.5gL-1,其中W1下部Diver平均鹽度最低,W5下部Diver平均鹽度最高。由于W2井安裝后土壤擾動(dòng)較大,低潮時(shí),井中水位低于上部Diver所在的位置高程,上部Diver位置由飽水帶變?yōu)榘鼩鈳�。此時(shí)所測(cè)壓力為負(fù)壓,但仍可作為地下水的水壓。利用廣義達(dá)西定律,對(duì)所有觀測(cè)井中的地下水流速進(jìn)行計(jì)算,估算出整個(gè)剖面長(zhǎng)度上海底地下水的排泄量(SGD)和入滲量分別是11.1 m2 d-1和21.0 m2 d-1。觀測(cè)井W4和W6之間的入滲量占整個(gè)剖面入滲量的42.6%,排泄量(SGD)占總排泄量的43.9%。本研究中的地下水排泄量是前人在本場(chǎng)地研究所得SGD的1.3倍,入滲量是其入滲量的1.4倍。
[Abstract]:To study the interaction of seawater and groundwater in coastal aquifer in coastal area, including the discharge of seabed groundwater, groundwater dynamics and solute transport, etc., and to evaluate the groundwater resources in coastal area. It is of great theoretical and practical significance to correctly distinguish the sources of nutrients and improve the aquiculture model of marine products. In the past, the study of sea water and groundwater exchange in coastal zone was mainly focused on sandy and gravel beaches, but there was little research on muddy tidal flat which was widely distributed in coastal areas both at home and abroad. In this paper, a typical muddy tidal flat section on the east coast of Laizhou Bay is selected as the experimental site to improve the single well used in the field observation before, and the method of setting up the "opposite well" observation well is adopted. The groundwater exchange capacity of seawater was estimated under the influence of seepage surface and density. The tidal beach profile studied in this paper is about 450 m long, with a slope of 1.8 鈥，

本文編號(hào)：2383820