1、ABSTRACTProposed expansion of extractive lime-rock mines near the MiamiDade County Northwest well field and Everglades wetland areas has garnered intense scrutiny by government, public, environmental stakeholders,and the media because of concern that mining will increase the risk of pathogen contami

2、nation. 由于擔心采礦工作會增加當地受病原體污染的危險，擴張對邁阿密戴德縣西北礦井地區以及佛羅里達大沼澤地地區的石灰巖礦山萃取工藝的提議已經受到了政府，公眾，環境利益攸關者以及媒體的密切關注。Rock mines are excavated to the same depth as the well fields primary producing zone. 與礦井區開采石灰巖礦山的主要生產區域挖掘的深度一致。The underlying karst Biscayne aquifer is a triple-porosity system characterized by (1) a

3、matrix of interparticle porosity and separate vug porosity; (2) touching-vug porosity that forms preferred, stratiform passageways; and, less commonly, (3) conduit porosity formed by thin solution pipes, bedding-plane vugs, and cavernous vugs. 卡斯特地貌的底層比斯坎含水層的三重孔隙系統的特點是(1)有基質粒子間的多孔性和單獨的溶洞多孔性特征：（2）接觸面

4、溶洞孔隙度主要以一種層狀通道的形式存在，但是比較少見。Existing ground-water flow and particle tracking models do not provide adequate information regarding the ability of the aquifer to limit the advective movement of pathogens and other contaminants. 現有的地下水流動和粒子跟蹤模型并沒有提供足夠的有關含水層能限制病原體和其他污染物對流運動的信息。Chemical transport and coll

5、oidal mobility properties have been delineated using conservative and microsphere-surrogate tracers for Cryptosporidium parvum. 化學運輸和膠體流動性能一直是通過標記有保守微粒體替代物示蹤劑的隱孢子蟲來顯示。Forced-gradient tests were executed by introducing conservative tracers into injection wells located 100 m (328 ft) from a municipal-

6、supply well. 強制梯度測試是通過將保守示蹤劑從市政供水井引入注入井100米處(328英尺)來執行的。Apparent mean advective velocity between the wells is one to two orders of magnitude greater than previously measured. Touching-vug, stratiform flow zones are efficient pathways for tracer movement at the well field. 各井之間的表觀平均對流速度大于預先測量值一到兩個數量級

7、。 接觸孔隙，層狀流區是在井場進行運動示蹤的有效途徑。The effective porosity for a continuum model between the point of injection and tracer recovery ranges from 2 to 4 percent and is an order of magnitude smaller than previously assumed.在注入點和示蹤復蘇點之間的連續介質模型的有效孔隙度范圍在2到4%,比此前假定的要小一個數量級。 Existing well-field protection zones were

8、 established using porosity estimates based on specific yield. 現有井場保護區是基于特定區域的孔隙度估計值建立起來的。The effective, or kinematic, porosity of a Biscayne aquifer continuum model is lower than the total porosity, because high velocities occur along preferential flow paths that result in faster times of travel th

9、an can be represented with the ground-water flow equation. 從有效性,或者運動學來看,比斯坎含水層連續介質模型的孔隙度要低于總孔隙度, 因為高速流動是沿著優先流體路徑發生的,這也導致更快的流速可以通過地下水的流動方程來表示。Tracer tests indicate that the relative ease of contaminant movement to municipal supply wells is much greater than previously considered.示蹤劑測試表明,污染物運動遷移到市政供水井

10、的容易程度遠大于以前。2.conclusionThe Northwest well field, Floridas largest municipal well field, is located on the eastern edge of an extractive limestone-rock mining district in north-central MiamiDade County. Mining activities create artificial lakes that are, in places, the same depth as the supply-well p

11、roduction zone. These borrow-pit lakes are within a 247- to 914-m (810- to 3,000-ft) distance of active supply wells. Consequently, there is considerable concern that if mine expansion continues, withdrawals are more likely to be influenced by the quality of lake-mine surface water, and the well fie

12、ld will require use of enhanceddisinfection and filtration treatment to remove protozoan pathogens, including Cryptosporidium parvum.西北井場是佛羅里達州最大的市政場井區,位于邁阿密戴德縣中北部石灰巖礦區的東部邊緣。在這些地方,與供水井相同深度的生產區域有采礦活動創造的人工湖泊。這些取土坑的湖泊離正在運作的供水井距離范圍為247914米之間，因此，如果繼續開發礦區，這就存在相當大的隱患，但撤銷開采項目就很可能會影響到人工湖及礦山區域地表水的水質，而且井區將強化消毒

13、及過濾處理來除去原生動物病原體，其中就包括隱孢子蟲。Laboratory and field tests have been coupled to examine potential pathways for solute and microbial contamination, filtration mechanisms that might impede microbial transport, and karst limestone well-field vulnerability issues. Intensive data-collection efforts have been c

14、ompleted and include laboratory column studies, detailed geologic site investigations, and hydraulic and field tracer tests. The assessment of some of these data is ongoing.實驗室實驗和現場測試被耦合起來檢查溶質和微生物污染的潛在途徑,而過濾機制可能會阻礙微生物運輸,從而導致喀斯特石灰巖井場的脆弱性問題。密集的數據收集工作已經完成,其中包括實驗的柱研究，以及詳細的地質調查和現場液壓示蹤試驗。其中的一些數據的評估正在進行中。T

15、he Biscayne aquifer underlies the Northwest well field and is formed by vertically repeating assemblages of principally carbonate lithofacies that delineate a cyclostratigraphy. These lithofacies are each characterized by specific pore classes that are characterized by highly permeable, touching-vug

16、 stratiform flow zones and uncommon bedding plane vugs (pore class I); lesspermeable matrix with mostly intergranular porosity and separate vugs (pore class II); and leaky, low-permeabilitylayers (pore class III). Most ground-water flow occurs within touching-vug pore space (vuggy pores that coalesc

17、e into interconnected pore space), forming tortuous stratiform pathways for advective movement of solutes and pathogens. Diffuse-carbonate flow occurs within matrix-dominated carbonate-rock flow zones, mostly formed by interparticle pore space. Minor, leaky lowpermeability flow characterizes micrite

18、-rich limestone layers that behave, at least locally, as a semiconfining unit.比斯坎含水層位于西北場區之下，通過垂直地多次重復地聚集大部分的碳酸巖巖相而形成了一種旋回地層，這些巖相以特定級別的有高滲透性的接觸孔洞氣相流動區以及不常見的層理面孔洞為特點（這是第一種氣孔）。少量的有滲透性的脈石和大多數顆粒孔隙以及獨立的孔洞形成第二級別的氣孔。有漏洞的，低滲透性的地層是第三類氣孔。大多數地下水流動發生在接觸溶洞氣孔空間從而為平流運動的溶解質和病原體形成了彎曲的層狀通道。二氧化碳的涌流運動發生在以脈石為主的碳酸鹽流區，這些區

19、域大部分是由粒子之間的氣孔空間形成。較小的，易漏的低滲透性的流區以富含泥晶灰巖的石灰巖地層作為最小的功能單位。An underdamped hydraulic response was observed during aquifer tests, reflecting the highly transmissive nature of the Biscayne aquifer. Ground-water occurs under unconfined or semiconfined conditions. Hydraulic tests indicated that the aquifer u

20、nderlying the Northwest well field is strongly influenced by stage levels in surrounding canals that are at a 2.4- to 3.2-km (1.5- to 2.0-mi) distance from supply wells.在水壓測試中觀察到液壓阻尼不足的反應現象，這反映了比斯坎含水層高速傳遞的本質特點。由于地下水在松散的或半松散的條件下形成，水力學測試表明西北廠井下的含水層受到了周圍離市政供水井2.4-3.2km遠的運河的強烈影響。Conservative tracers (rh

21、odamine WT and deuterium) were introduced into an injection well located 100 m (328ft) from a production well in April 2003. Mean velocity of the tracer pulse between the point of injection and recovery (supply well) seems to be one to two orders of magnitude greater than measurements obtained by MiamiDade County in 199899. An assessment of the outcome of a suite of conservative and colloidal tracers (deuterium, halon, SF6, a