Abstract: A quantitative classification of carbonate aquifers based on hydrodynamic behaviour is introduced. This type of classification is necessary to understand the physical functioning of carbonate hydrogeological systems and to provide a realistic interpretation of field data. Carbonate aquifers are generally considered as karst systems. However, geomorphology and aquifer geology alone are insufficient for determining hydrodynamic behaviour. Analysis of spring and well hydrographs based on analytical solutions is applied to establishing a quantitative classification. A base-flow recession coefficient is used as an indicator of hydrodynamic behaviour. Detailed numerical analysessuggest that carbonate systems can be classified into two distinct groups based on hydrodynamic behaviour. The physical processes depend on a combination of hydraulic and geometric parameters, and their functional relationships can be quantitatively determined. The proposed classification methodology involves making an assumption about aquifer type, estimating aquifer properties from hydrograph data, and comparing the results with field observations. The proposed classification methodology was applied toaquifers representing the two groups of carbonate systems. In both cases the applied methods revealed crucial information about hydrodynamic functioning of the investigated systems. While the studied limestone aquifer showed karstic hydrodynamic behaviour, the investigation of a dolomite aquifer disproves a priori assumptions on karstic flow conditions. Dolomite aquifers represent an ambiguous group of carbonates and require caution in the selection of investigation tools and interpretation of hydrogeological data. The introduced methodology provides a reliable means of determining the hydrodynamic functioning of an aquifer and supports the quantitative classification of carbonate hydrogeological systems.
摘要：介紹了基於流體動力學行為的碳酸鹽含水層的定量分類。這種類型的分類對於理解碳酸鹽水文地質系統的物理功能並提供對現場數據的真實解釋是必要的。碳酸鹽含水層通常被認為是巖溶系統。然而，僅地貌學和含水層地質學不足以確定水動力行為。基於解析解的泉水和井水位圖的分析被用於建立定量分類。基流衰退係數用作水動力行為的指標。詳細的數值分析表明，根據水動力學行為，碳酸鹽體系可以分為兩個不同的組。物理過程取決於水力和幾何參數的組合，並且可以定量確定它們的功能關係。擬議的分類方法涉及對含水層類型進行假設，從水文數據估計含水層性質，並將結果與現場觀測結果進行比較。擬建立的分類方法適用於代表兩組碳酸鹽系統的含水層。在這兩種情況下，所應用的方法都揭示了有關所研究系統的水動力功能的關鍵信息。雖然所研究的石灰巖含水層顯示出巖溶水動力行為，但對白雲巖含水層的研究證明了對巖溶水流條件的先驗假設。白雲巖含水層代表了一組含碳酸鹽，在選擇調查工具和解釋水文地質數據時需要謹慎。引入的方法為確定含水層的水動力功能提供了可靠的手段，並可用於碳酸鹽巖水文地質系統的定量分類。
Abstract: Newly acquired high-quality data are being used to reinterpret the Surat Basin flow systems of the Great Artesian Basin (GAB) in Australia. This paper revisits and updates previous interpretations of flow in the Hutton Sandstone with detailed analysis of the Dawson River area in the northern Surat Basin. Combining analysis of high-resolution permeability measurements with hydraulic head and hydrochemistry data supports the contention that there is significant flow towards the northeast, counter to the canonical regional flow conceptualisation of the GAB. The analysis in this work better identifies the likely discharge to be in the area that the Dawson River intersects the Hutton Sandstone. Heterogeneity in physical and hydrochemical properties suggests that local flowpaths are more complex than previously thought and, at least in this part of the Hutton aquifer, very little recharge contributes to flow deeper in the basin. These results provide a firm basis on which to refine and develop numerical hydrodynamic models of the basin, at least for the Hutton aquifer.
摘要：新獲得的高質量數據正用於重新解釋澳大利亞大自流盆地（GAB）中Surat盆地的流動系統。本文通過對Surat盆地北部的Dawson河地區的詳細分析，回顧並更新了先前在Hutton砂巖中流動的解釋。將高解析度滲透率測量結果與水頭和水化學數據相結合，支持了在東北方向有明顯流動的結論，這與GAB的規範化的區域流動概念相反。這項工作中的分析可以更好地確定Dawson河與Hutton砂巖相交區的可能排洩區。物理和水化學性質的非均質性表明，局部的流動路徑比以前認為的更複雜，至少在Hutton含水層部分，很少的補給將對盆地中深部流動有貢獻。這些結果為包括Hutton含水層在內的盆地數值水動力模型的完善和發展提供了堅實的基礎。
Abstract: Quantitative field methods were used to refine eco-hydrogeological conceptual models of terrestrial groundwater dependent ecosystems (GDEs) in the Great Artesian Basin (GAB), Queensland, Australia. There are few studies which report on the effectiveness of published methods to ground truth the occurrence of assumed GDEs, particularly in areas subject to coal seam gas development. Using a combination of methods, a field investigation was completed at four sites in vegetation communities dominated by river red gum (Eucalyptus camaldulensis) in areas overlying the GAB. Multiple lines of evidence determined the predominant source of water utilised by large trees at each locality to assess if the terrestrial ecosystems were dependent on the presence of groundwater. Methods included soil coring to observe tree rooting depth and underlying hydrogeological conditions, matching of soil moisture with leaf water potential, and analysis of naturally occurring stable isotopes of hydrogen and oxygen found in tree xylem, soil moisture and groundwater. Results indicate that despite study locations being conceptually mapped as GDEs, trees located within at least three of the four assessed sites were predominantly utilising shallow sources of soil moisture located above the regional water-table aquifer. Also, rooting depths of targeted tree species were consistently much shallower (maximum depth 7.6 mbgl) than what is commonly reported in literature (12–22.6 mbgl). The findings highlight the importance of ground-truthing to refine the eco-hydrogeological conceptual models of GDEs using a combination of methods to create a holistic understanding of water sources for terrestrial vegetation communities in areas vulnerable to groundwater abstraction.
摘要：在澳大利亞昆士蘭州的大自流盆地，採用定量化的野外方法對依賴地下水的陸地生態系統的生態水文地質概念模型進行了改進。對已出版方法的有效性來確定假設依賴地下水的生態系統是否存在的研究不多見，特別是在受煤層氣開發影響的地區。在大自流盆地上覆區域，運用多種方法，完成了以河紅樹膠（Eucalyptus camaldulensis）為主的植被群落的四個樣點的野外調查。多方面的證據確定了每個地方的樹木依賴的主要水源，以此來評估陸地生態系統是否依賴於地下水作為主要水源。採用的方法包括：土壤取芯以觀測樹木生根深度及下伏水文地質條件；土壤水分與葉水勢的匹配；樹木木質部，土壤水分和地下水中天然存在的穩定氫氧同位素分析。結果表明，儘管研究地點在概念上被描述為依賴地下水的生態系統，但四個評估地點中至少有三個地點內的樹木主要利用位於區域地下含水層上方的淺層土壤水分作為水分來源。而且，目標樹種的生根深度始終比通常文獻中報導的（12–22.6 mbgl）淺得多（最大深度為7.6 mbgl）。研究結果強調了現場驗證的重要性，即利用各種方法的組合來完善依賴地下水型生態系統的生態水文地質概念模型，從而為易受地下水開採影響地區的陸生植被群落建立對水源的整體認識。
Abstract: Groundwater chemical and isotopic variability are used to identify and map temporal changes in the paleo-lacustrine environment and the long-term climate trends in the Closed Basin of the San Luis Valley, Colorado, USA. Total dissolved solids, water color,13C, SO42-, Cl-, and Na+excess are used to identify chemical reaction zones. The reaction zones include methanogenic zones, which represent organic-rich reducing shallow lake conditions; gypsum and halite dissolution zones, which represent saline and playa lakes; and ion exchange zones, which represent organic-rich lakes. The reaction zone maps and vertical stratification depict both long-term and rapid changes in the paleo-lacustrine environmental conditions and changes in the climate regime of the Closed Basin. Based on the reaction zone mapping, the general scheme of the late Pleistocene-Holocene environmental regime of the Closed Basin has been worked out. The upper portion of the confined aquifer was deposited in the organic-rich late Pleistocene Lake Sipapu, which filled the Closed Basin after the draining of the Plio-Pleistocene Lake Alamosa. As the organic-rich lake shrank in size due to the drying climate, the unconfined aquifer sediments were deposited as fluvial sediments and in a series of smaller string lakes. In the string lakes, organic-rich sediments were deposited, and gypsum and halite precipitated as the lakes fluctuated between swamps, fresh and saline lakes, and playas.
摘要：利用地下水化學和同位素的變異性，識別和繪製了美國科羅拉多州San Luis山谷封閉盆地中古湖泊沉積環境隨時間變化與長期氣候趨勢。根據地下水中溶解總固體、水色、13C，SO42-,，Cl-，以及Na+過量的差異劃分了化學反應帶，反應帶包括：甲烷產生帶，代表富含有機物減少的淺湖環境；石膏及巖鹽溶解帶，代表鹽湖和幹鹽湖環境；以及離子交換帶，代表有機質豐富的湖泊環境。反應分帶圖和垂直層理，描述了封閉盆地中古湖泊環境條件與氣候條件隨時間變化與長期變化趨勢。基於反應帶分區製圖，研究確定了封閉盆地晚更新世-全新世環境的總體概況。在上新世-更新世Alamosa湖洩水後，Sipapu湖填滿封閉盆地，因此富含有機質的承壓含水層上部形成於晚更新世沉積。由於氣候變幹，富含有機質的湖泊規模縮小，潛水含水層沉積物為河流相沉積物和一系列較小的串狀湖泊相沉積物。在串狀湖泊相中的沉積物富含有機質，由於湖泊在沼澤、淡水湖、鹽湖以及幹鹽湖之間的不斷轉變，同時造成石膏和巖鹽沉積。
Abstract: Coal seam gas (CSG) or coal bed methane developments in sedimentary basins, such as the Great Artesian Basin (GAB) in Australia, have the potential to impact on aquifers overlying and underlying the target coal formations. The extent to which this may occur depends upon the degree of hydrogeological connectivity between the coal formations and the surrounding aquifers or aquifer systems, with general implications for groundwater management. In southeast Australia, one such aquifer system, the Condamine Alluvium (CA), overlies the Walloon Coal Measures (WCM), which is a formation of the GAB and also a target for CSG production. To investigate the connectivity between the two systems, multiple lines of investigation were employed involving field investigations, data gathering and analysis (including reinterpretation of geology, multivariate hydrochemistry analysis, regional water-level mapping, drilling and coring across the contact zone, multiple piezometer installations, long-term pumping tests, groundwater-level monitoring and local-scale modelling). The study found a low level of connectivity between the GAB and the overlying CA. A layer of undifferentiated basement clay (referred to as the 『transition zone』) – a mixture of alluvial clay and weathered basement – provides an effective impediment to flow across the CA and the underlying GAB formations. Results from the study potentially have wider application across the GAB and sedimentary basins where younger alluvial sediments associated with river systems frequently overlie the erosional surface.
摘要:在諸如澳大利亞大自流盆地（GAB）的沉積盆地中的煤層氣（CSG）或煤層甲烷的開發可能會影響目標煤層上覆和下伏的含水層。其影響程度取決於煤層與周邊含水層或含水系統之間的水力聯繫，這在地下水管理方面具有普遍意義。澳大利亞東南部的含水系統，也就是Condamine衝積層（CA），上覆於Walloon煤系（WCM），即GAB中煤層氣開採的目標煤層。為研究這兩個系統之間的連通性，採用多種調查方法，包括現場調查，數據收集和分析（包括地質數據再分析，多變量水化學分析，區域水位繪製，接觸帶鑽孔和取芯，多個測壓計安裝，長期抽水試驗，地下水位監測和局部尺度的模擬）。研究發現GAB與上層CA之間的連通性較差。一層未分化的基底粘土（稱為「過渡帶」），也就是衝積粘土和風化基底的混合物，有效阻礙了流體在CA和其下的GAB地層之間流動。該研究結果有望在GAB和那些與河流系統相聯的更年輕衝積沉積頻繁覆蓋侵蝕面的沉積盆地中得到更廣泛應用。