Estimated hydrologic characteristics of shallow aquifer systems in the Valley and Ridge, the Blue Ridge, and the Piedmont Physiographic Provinces based on analysis of streamflow recession and base flow

1996 ◽  
pp. B1-B58 ◽  
Author(s):  
A.T. Rutledge ◽  
T.O. Mesko
Keyword(s):  
Base Flow ◽  
Shallow Aquifer ◽  
Blue Ridge ◽  
Aquifer Systems

Hydraulics of horizontal wells in fractured shallow aquifer systems

2003 ◽  
Vol 281 (1-2) ◽  
pp. 147-158 ◽  
Author(s):  
Eungyu Park ◽  
Hongbin Zhan
Keyword(s):  
Horizontal Wells ◽  
Shallow Aquifer ◽  
Aquifer Systems

scholarly journals Multi-gauge Calibration for Modeling the Semi-Arid Santa Cruz Watershed in Arizona-Mexico Border Area Using SWAT

2012 ◽  
Vol 5 ◽  
pp. ASWR.S9410 ◽  
Author(s):  
Rewati Niraula ◽  
Laura M. Norman ◽  
Thomas Meixner ◽  
James B. Callegary
Keyword(s):  
Assessment Tool ◽  
Soil Layer ◽  
Watershed Modeling ◽  
Base Flow ◽  
Shallow Aquifer ◽  
Return Flow ◽  
Monitoring Site ◽  
Santa Cruz ◽  
Mexico Border ◽  
Semi Arid

In most watershed-modeling studies, flow is calibrated at one monitoring site, usually at the watershed outlet. Like many arid and semi-arid watersheds, the main reach of the Santa Cruz watershed, located on the Arizona-Mexico border, is discontinuous for most of the year except during large flood events, and therefore the flow characteristics at the outlet do not represent the entire watershed. Calibration is required at multiple locations along the Santa Cruz River to improve model reliability. The objective of this study was to best portray surface water flow in this semi-arid watershed and evaluate the effect of multi-gauge calibration on flow predictions. In this study, the Soil and Water Assessment Tool (SWAT) was calibrated at seven monitoring stations, which improved model performance and increased the reliability of flow predictions, in the Santa Cruz watershed. The most sensitive parameters to affect flow were found to be curve number (CN2), soil evaporation and compensation coefficient (ESCO), threshold water depth in shallow aquifer for return flow to occur (GWQMN), base flow alpha factor (ALPHA_BF), and effective hydraulic conductivity of the soil layer (CH_K2). In comparison, when the model was established with a single calibration at the watershed outlet, flow predictions at other monitoring gauges were inaccurate. This study emphasizes the importance of multi-gauge calibration to develop a reliable watershed model in arid and semi-arid environments. The developed model, with further calibration of water quality parameters will be an integral part of the Santa Cruz Watershed Ecosystem portfolio Model (SCWEPM), an online decision support tool, to assess the impacts of climate change and urban growth in the Santa Cruz watershed.

scholarly journals Hydrogeochemical contrasts in the shallow aquifer systems of the Lower Katari Basin and Southern Poopó Basin, Bolivian Altiplano

2021 ◽  
Vol 105 ◽  
pp. 102914 ◽  
Author(s):  
Israel Quino Lima ◽  
Mauricio Ormachea Muñoz ◽  
Oswaldo Eduardo Ramos Ramos ◽  
Jorge Quintanilla Aguirre ◽  
Jyoti Prakash Maity ◽  
...  
Keyword(s):  
Shallow Aquifer ◽  
Aquifer Systems ◽  
Bolivian Altiplano

Closing a scale-gap in Earth observation using regional-scale airborne geophysics in the lower Mississippi Valley

2021 ◽  
Author(s):  
Burke Minsley ◽  
James Rigby ◽  
Stephanie James ◽  
Bethany Burton ◽  
Katherine Knierim ◽  
...  
Keyword(s):  
United States ◽  
Groundwater Resources ◽  
Regional Scale ◽  
The United States ◽  
Shallow Aquifer ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Aquifer Systems ◽  
Regional Hydrogeology ◽  
New Madrid

<p>Critical groundwater resources and hidden seismic hazards underly much of the Mississippi Alluvial Plain. Spanning nearly 100,000 square kilometers across seven states, this region hosts one of the most prolific shallow aquifer systems in the United States that supports a $12 billion agricultural economy amidst chronic groundwater decline. Further, underlying fault structures of the Reelfoot Rift and New Madrid Seismic Zone represent an important and poorly understood hazard with a complex pattern of historical impacts. Despite its societal and economic importance, mapping of shallow subsurface architecture with spatial resolution needed for effective management is insufficient. Here, we report the results of 40,000 flight-line-kilometers of electromagnetic, magnetic, and radiometric data collectively providing a system-scale snapshot of an entire aquifer system, the first such effort in the United States. This survey enables new understanding of the regional hydrogeology while also revealing previously unseen large vertical displacements (exceeding 50 m) in the uppermost Tertiary units within the New Madrid Seismic Zone.</p>

Hydrochemical interpretation of groundwater flow systems in Quaternary sediments of southern Ontario

1986 ◽  
Vol 23 (7) ◽  
pp. 938-947 ◽  
Author(s):  
K. W. F. Howard ◽  
P. Beck
Keyword(s):  
Major Ions ◽  
Regional Scale ◽  
Shallow Aquifer ◽  
Sediment Geochemistry ◽  
Quaternary Sediments ◽  
Southern Ontario ◽  
Water Types ◽  
Regional Flow ◽  
Aquifer Systems ◽  
Composite Flow

Shallow aquifer systems in surficial Quaternary sediments are geometrically complex, with highly variable hydraulic characteristics. Consequently these systems are extremely difficult to assess hydrogeologically using conventional investigation techniques and are often poorly understood. In a 500 km2 area of southern Ontario, hydrochemical techniques were used to investigate the hydraulic integrity and regional flow behaviour of 14 aquifer systems defined within 100 m of Quaternary overburden. This type of approach had been used successfully in more extensive bedrock aquifer systems but had not previously been applied on a regional scale to shallow Quaternary systems where sediment geochemistry and flow conditions are highly variable and rarely known. The study involved analysis of over 260 well waters for pH, major ions (Ca, Mg, Na, K, HCO3, Cl, and SO4) and subsidiary ions (NO3, I, Br, and F). Selected samples were analyzed for tritium.The groundwaters are classified into eight water types, two of which are sodium chloride in character and of bedrock origin. Of the remaining six, four are related by a chemical evolutionary sequence showing transition from a tritiated (> 30 TU), low-iodide (< 5 μg/L) CaHCO3 recharge water to an ion-exchanged, NaHCO3 water low in tritium (< 15 TU) and enriched in iodide (> 15 μg/L). The existence of this sequence implies a regional, composite flow system involving seven supposedly discrete aquifer systems.The two remaining water types are recent tritiated waters (> 20 TU) contaminated by road salt (Cl > 40 mg/L) and agricultural nitrate (NO3 > 10 mg/L). Together with the CaHCO3 waters these clearly delineate major areas of recharge and show that the covering of Halton Till is extensively permeable.

scholarly journals Distinct stores and the routing of water in the deep critical zone of a snow-dominated volcanic catchment

2019 ◽  
Vol 23 (11) ◽  
pp. 4661-4683 ◽  
Author(s):  
Alissa White ◽  
Bryan Moravec ◽  
Jennifer McIntosh ◽  
Yaniv Olshansky ◽  
Ben Paras ◽  
...  
Keyword(s):  
Shallow Groundwater ◽  
Critical Zone ◽  
Shallow Aquifer ◽  
Precipitation Pattern ◽  
Fractured Aquifer ◽  
Aquifer System ◽  
Major Ion ◽  
Welded Tuff ◽  
Aquifer Systems ◽  
Isotopic Analyses

Abstract. This study combines major ion and isotope chemistry, age tracers, fracture density characterizations, and physical hydrology measurements to understand how the structure of the critical zone (CZ) influences its function, including water routing, storage, mean water residence times, and hydrologic response. In a high elevation rhyolitic tuff catchment in the Jemez River Basin Critical Zone Observatory (JRB-CZO) within the Valles Caldera National Preserve (VCNP) of northern New Mexico, a periodic precipitation pattern creates different hydrologic flow regimes during spring snowmelt, summer monsoon rain, and fall storms. Hydrometric, geochemical, and isotopic analyses of surface water and groundwater from distinct stores, most notably shallow groundwater that is likely a perched aquifer in consolidated collapse breccia and deeper groundwater in a fractured tuff aquifer system, enabled us to untangle the interactions of these groundwater stores and their contribution to streamflow across 1 complete water year (WY). Despite seasonal differences in groundwater response due to water partitioning, major ion chemistry indicates that deep groundwater from the highly fractured site is more representative of groundwater contributing to streamflow across the entire water year. Additionally, the comparison of streamflow and groundwater hydrographs indicates a hydraulic connection between the fractured welded tuff aquifer system and streamflow, while the shallow aquifer within the collapse breccia deposit does not show this same connection. Furthermore, analysis of age tracers and oxygen (δ18O) and stable hydrogen (δ2H) isotopes of water indicates that groundwater is a mix of modern and older waters recharged from snowmelt, and downhole neutron probe surveys suggest that water moves through the vadose zone both by vertical infiltration and subsurface lateral flow, depending on the lithology. We find that in complex geologic terrain like that of the JRB-CZO, differences in the CZ architecture of two hillslopes within a headwater catchment control water stores and routing through the subsurface and suggest that shallow groundwater does not contribute significantly to streams, while deep fractured aquifer systems contribute most to streamflow.

scholarly journals Hydrogeological and geochemical overview of the karst aquifers in the Apuan Alps (Northwestern Tuscany, Italy)

2016 ◽  
Author(s):  
Matia Menichini ◽  
Marco Doveri ◽  
Leonardo Piccini
Keyword(s):  
Geological Structure ◽  
Base Flow ◽  
Metamorphic Rocks ◽  
Mountain Range ◽  
Mixing Processes ◽  
Karst Springs ◽  
Carbonate Aquifers ◽  
Aquifer Systems ◽  
Wide Range ◽  
Apuan Alps

Apuan Alps, in north-western Tuscany (Italy), have a very complex geological structure. For this reason karst springs show very different behaviours according to the geological setting of aquifer systems. More than 80 springs are fed by carbonate aquifers; flow rates (Q) range from 10 to 1600 L/s, in average, temperatures range from 8 to 15 °C. Deep and very slow groundwater flow feed some low-thermal springs (20-30 °C). Major karst springs (Q > 100 L/s) are concentrated in two altimetry ranges, one from 200 to 300 m a.s.l. in the seaward side (SW-NW) and a second one from 500 to 600 m a.s.l. on the inner (NE-SE) side of the mountain range. Most of the springs are the final destination of large karst systems developed in meta-dolomite and marbles characterized by a very rapid flow. Some springs have a regular regime and are fed by bathyphreatic systems in metamorphic rocks or by carbonate aquifers with a major contribution of fissured drainage in non-metamorphic rocks. Large physical-chemical variations, both in space and time, are observed as a consequence of lithological heterogeneity, mixing processes and hydrodynamic conditions. Most waters are of the Ca-HCO3 type, but Ca-SO4 and Na-Cl facies are also present. A wide range of electrical conductivity is recorded, with values between 0.1 μS/cm and 10 μS/cm. Significant differences in the average isotopic signature (e.g. δ18O from -5.5 to -8.5‰) of the “base-flow” are registered due to the variability of hydrogeological basins dimension and their distribution in terms of altitude range and side. In some cases, springs with similar chemical features and located close to each other, point out very different isotopes signature, thus highlighting complicated flow path of groundwater. Furthermore, different seasonal evolutions of isotopic signatures are registered.

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