Water Resources of the Dakota Aquifer in Kansas

The Dakota aquifer system underlies most of the western two-thirds of Kansas and includes sandstone units in the Cretaceous Dakota, Kiowa, and Cheyenne Sandstone formations. The underlying Jurassic Morrison Formation in southwest Kansas is also considered by state statute to be part of the Dakota system. The Dakota aquifer has been developed as a water-supply source where the groundwater is fresh or only slightly saline and where other more easily obtained water supplies are not available. A total of 2,237 wells with active water rights and active uses made of water as of the end of 2011 were determined to produce greater than 5% of their total yield from the Dakota aquifer. Most of these wells are located where the Dakota aquifer underlies the High Plains aquifer (HPA) in southwest Kansas. In the 36 counties in which water-right-permitted wells pump partially or solely from the Dakota aquifer, the wells with Dakota yield are estimated to comprise 9% of the total of wells with water-right permits in all aquifers. Most (78%) of the water-right-permitted wells that draw part or all of their water from the Dakota aquifer are used for irrigation. Stock, municipal, and industrial wells comprise nearly all of the other uses (9.6%, 8.9%, and 2.2%, respectively, of the wells with some Dakota yield). The mean annual volume of water used from the Dakota aquifer by water-right-permitted wells in Kansas is estimated to have been 117,000 acre-ft/yr (1.44 x 108 m3/yr) from 2006 to 2010. The use was greatest in southwest Kansas (approximately 86% of the total Dakota use). The mean annual use for other regions ranged from approximately 0.5% of the total Dakota use for west-central Kansas, to 2.4% for central, 2.9% for south-central, and 8.1% for north-central Kansas. Although Dakota water use in north-central Kansas was much lower than in southwest Kansas, the percent Dakota use relative to total use from all aquifers was the highest (nearly 20%) of all the regions. The percent Dakota use compared to total use from all aquifers for the other regions is 5.2% for southwest, 2.5% for central, 2.0% for south-central, and 0.4% for west-central Kansas. About 90% of the mean annual use from the Dakota aquifer during 2006-2010 was for irrigation, most of which was in southwest Kansas. For stock and municipal purposes, water usage was nearly 4% each of the total volume pumped from the Dakota aquifer. However, municipal demands accounted for 41% and 18% of the total use from the Dakota in central and north-central Kansas, respectively. The total number of "domestic" wells, defined as those for which water-right permits are not required, that currently produce most or all of their water from the Dakota aquifer in Kansas is estimated to be more than 11,000 (about 8,000 for north-central and central Kansas and nearly 3,200 for south-central, west-central, and southwest Kansas). Water use from the Dakota aquifer by "domestic" wells is estimated to be 4,800 acre-ft/yr (5.9 x 106 m3/yr) in central Kansas, 1,500 acre-ft/yr (1.9 x 106 m3/yr) in north-central Kansas, and a total of 1,700 acre-ft/yr (2.1 x 106 m3/yr) in south-central, west-central, and southwest Kansas. The total "domestic" well use (about 8,000 acre-ft/yr) is about 6.4% of the approximately 125,000 acre-ft/yr (1.54 x 108 m3/yr) pumped from the Dakota aquifer by both permitted and "domestic" wells in Kansas. The processes of mixing, reactive cation exchange, and mineral dissolution and precipitation have produced a complex range of chemical characteristics for groundwater in the Dakota aquifer. Water quality in the aquifer ranges from very fresh (<300 mg/L total dissolved solids [TDS]) to saltwater (>10,000 mg/L TDS). Freshwaters in the outcrop and subcrop portions of the Dakota aquifer in north-central and central Kansas are usually calcium-bicarbonate type waters. Calcium-sulfate type water in some regions can result from one of two processes: (1) weathering of pyrite in shales in Dakota strata and concomitant dissolution of calcite or dolomite and (2) recharge from upper Cretaceous strata that was affected by the same processes or by dissolution of gypsum. Large areas of the Dakota aquifer contain saline water (sodium-chloride type water) that was derived from the upward intrusion of saltwater from underlying Permian units, especially the Cedar Hills Sandstone in central and north-central Kansas. The saltwater is derived from the dissolution of evaporite deposits containing rock salt (halite) in the Permian. The salinity of groundwater in the Dakota aquifer generally increases with depth, particularly across substantial shale units of appreciable lateral extent that confine or separate aquifer units. Sodium-bicarbonate type water, which exists in parts of the confined Dakota aquifer in central and west-central Kansas, is generated by the flushing of saline water from the aquifer by groundwater recharge of calcium-bicarbonate or calcium-sulfate types. During this process, calcium (and magnesium) in the freshwater is exchanged for sodium on clays in Dakota strata. Fluoride concentrations increase in the sodium-bicarbonate water as a result of dissolution of calcium-containing fluoride minerals during the decrease in calcium in the groundwater caused by the exchange process. Fluoride concentrations exceed the maximum contaminant level (MCL) of 4 mg/L for public drinking water supply in some areas of the confined Dakota aquifer. About 10% of the sample records for the Dakota aquifer exceed the MCL for arsenic and the action level for lead, although some of the high lead values could be related to lead in plumbing systems. Uranium concentration and the radioactivity from radium isotopes and alpha particles exceed the MCL for public drinking waters in a small percentage of Dakota groundwaters. Many other natural constituents and properties in Dakota waters exceed recommended or suggested levels for drinking water, such as TDS, chloride, sulfate, iron, manganese, and ammonium ion concentrations, especially in saline water in the confined aquifer and in groundwaters that have chemically reducing conditions. The main contaminant from anthropogenic activities in Dakota groundwater is nitrate. Nitrate-nitrogen concentrations exceeding the MCL of 10 mg/L primarily occur in shallow wells in the unconfined aquifer in central and north-central Kansas. The expected sources are animal and human waste and fertilizer that enter groundwaters by shallow recharge or through the annular space of poorly constructed wells. Development of the Dakota aquifer has been dependent on both the hydrogeologic properties of the aquifer and the salinity of the groundwater. The Kansas Geological Survey has identified an area of nearly fresh to slightly saline waters in upper Dakota strata that could be important for future water supplies. The area is triangular in shape, with its base along the south lines of Sheridan and Graham counties and its northern extent into south-central Norton County. Another factor in aquifer development is the decline in the water table in the HPA where it overlies and is hydraulically connected to the Dakota aquifer in southwest Kansas. Many new wells have been completed in both the HPA and underlying Dakota strata. In cases in which the new construction is a replacement well, the previous well was often only completed in the HPA. Thus, the percentage of wells completed in both aquifers is increasing. Continued assessment of the water resources potential of the Dakota aquifer is especially needed in southwest Kansas but is difficult due to the very limited data for depth-to-water measurements in the Dakota in that area. A selected group of wells across the Dakota in southwestern Kansas should be equipped with continuous monitoring equipment so that a better understanding of the relationship between the Dakota and the overlying HPA can be obtained

Water Resources of the Dakota Aquifer in Kansas

The Dakota aquifer system underlies most of the western two-thirds of Kansas and includes sandstone units in the Cretaceous Dakota, Kiowa, and Cheyenne Sandstone formations. The underlying Jurassic Morrison Formation in southwest Kansas is also considered by state statute to be part of the Dakota system. The Dakota aquifer has been developed as a water-supply source where the groundwater is fresh or only slightly saline and where other more easily obtained water supplies are not available. A total of 2,237 wells with active water rights and active uses made of water as of the end of 2011 were determined to produce greater than 5% of their total yield from the Dakota aquifer. Most of these wells are located where the Dakota aquifer underlies the High Plains aquifer (HPA) in southwest Kansas. In the 36 counties in which water-right-permitted wells pump partially or solely from the Dakota aquifer, the wells with Dakota yield are estimated to comprise 9% of the total of wells with water-right permits in all aquifers. Most (78%) of the water-right-permitted wells that draw part or all of their water from the Dakota aquifer are used for irrigation. Stock, municipal, and industrial wells comprise nearly all of the other uses (9.6%, 8.9%, and 2.2%, respectively, of the wells with some Dakota yield). The mean annual volume of water used from the Dakota aquifer by water-right-permitted wells in Kansas is estimated to have been 117,000 acre-ft/yr (1.44 x 108 m3/yr) from 2006 to 2010. The use was greatest in southwest Kansas (approximately 86% of the total Dakota use). The mean annual use for other regions ranged from approximately 0.5% of the total Dakota use for west-central Kansas, to 2.4% for central, 2.9% for south-central, and 8.1% for north-central Kansas. Although Dakota water use in north-central Kansas was much lower than in southwest Kansas, the percent Dakota use relative to total use from all aquifers was the highest (nearly 20%) of all the regions. The percent Dakota use compared to total use from all aquifers for the other regions is 5.2% for southwest, 2.5% for central, 2.0% for south-central, and 0.4% for west-central Kansas. About 90% of the mean annual use from the Dakota aquifer during 2006-2010 was for irrigation, most of which was in southwest Kansas. For stock and municipal purposes, water usage was nearly 4% each of the total volume pumped from the Dakota aquifer. However, municipal demands accounted for 41% and 18% of the total use from the Dakota in central and north-central Kansas, respectively. The total number of "domestic" wells, defined as those for which water-right permits are not required, that currently produce most or all of their water from the Dakota aquifer in Kansas is estimated to be more than 11,000 (about 8,000 for north-central and central Kansas and nearly 3,200 for south-central, west-central, and southwest Kansas). Water use from the Dakota aquifer by "domestic" wells is estimated to be 4,800 acre-ft/yr (5.9 x 106 m3/yr) in central Kansas, 1,500 acre-ft/yr (1.9 x 106 m3/yr) in north-central Kansas, and a total of 1,700 acre-ft/yr (2.1 x 106 m3/yr) in south-central, west-central, and southwest Kansas. The total "domestic" well use (about 8,000 acre-ft/yr) is about 6.4% of the approximately 125,000 acre-ft/yr (1.54 x 108 m3/yr) pumped from the Dakota aquifer by both permitted and "domestic" wells in Kansas. The processes of mixing, reactive cation exchange, and mineral dissolution and precipitation have produced a complex range of chemical characteristics for groundwater in the Dakota aquifer. Water quality in the aquifer ranges from very fresh (<300 mg/L total dissolved solids [TDS]) to saltwater (>10,000 mg/L TDS). Freshwaters in the outcrop and subcrop portions of the Dakota aquifer in north-central and central Kansas are usually calcium-bicarbonate type waters. Calcium-sulfate type water in some regions can result from one of two processes: (1) weathering of pyrite in shales in Dakota strata and concomitant dissolution of calcite or dolomite and (2) recharge from upper Cretaceous strata that was affected by the same processes or by dissolution of gypsum. Large areas of the Dakota aquifer contain saline water (sodium-chloride type water) that was derived from the upward intrusion of saltwater from underlying Permian units, especially the Cedar Hills Sandstone in central and north-central Kansas. The saltwater is derived from the dissolution of evaporite deposits containing rock salt (halite) in the Permian. The salinity of groundwater in the Dakota aquifer generally increases with depth, particularly across substantial shale units of appreciable lateral extent that confine or separate aquifer units. Sodium-bicarbonate type water, which exists in parts of the confined Dakota aquifer in central and west-central Kansas, is generated by the flushing of saline water from the aquifer by groundwater recharge of calcium-bicarbonate or calcium-sulfate types. During this process, calcium (and magnesium) in the freshwater is exchanged for sodium on clays in Dakota strata. Fluoride concentrations increase in the sodium-bicarbonate water as a result of dissolution of calcium-containing fluoride minerals during the decrease in calcium in the groundwater caused by the exchange process. Fluoride concentrations exceed the maximum contaminant level (MCL) of 4 mg/L for public drinking water supply in some areas of the confined Dakota aquifer. About 10% of the sample records for the Dakota aquifer exceed the MCL for arsenic and the action level for lead, although some of the high lead values could be related to lead in plumbing systems. Uranium concentration and the radioactivity from radium isotopes and alpha particles exceed the MCL for public drinking waters in a small percentage of Dakota groundwaters. Many other natural constituents and properties in Dakota waters exceed recommended or suggested levels for drinking water, such as TDS, chloride, sulfate, iron, manganese, and ammonium ion concentrations, especially in saline water in the confined aquifer and in groundwaters that have chemically reducing conditions. The main contaminant from anthropogenic activities in Dakota groundwater is nitrate. Nitrate-nitrogen concentrations exceeding the MCL of 10 mg/L primarily occur in shallow wells in the unconfined aquifer in central and north-central Kansas. The expected sources are animal and human waste and fertilizer that enter groundwaters by shallow recharge or through the annular space of poorly constructed wells. Development of the Dakota aquifer has been dependent on both the hydrogeologic properties of the aquifer and the salinity of the groundwater. The Kansas Geological Survey has identified an area of nearly fresh to slightly saline waters in upper Dakota strata that could be important for future water supplies. The area is triangular in shape, with its base along the south lines of Sheridan and Graham counties and its northern extent into south-central Norton County. Another factor in aquifer development is the decline in the water table in the HPA where it overlies and is hydraulically connected to the Dakota aquifer in southwest Kansas. Many new wells have been completed in both the HPA and underlying Dakota strata. In cases in which the new construction is a replacement well, the previous well was often only completed in the HPA. Thus, the percentage of wells completed in both aquifers is increasing. Continued assessment of the water resources potential of the Dakota aquifer is especially needed in southwest Kansas but is difficult due to the very limited data for depth-to-water measurements in the Dakota in that area. A selected group of wells across the Dakota in southwestern Kansas should be equipped with continuous monitoring equipment so that a better understanding of the relationship between the Dakota and the overlying HPA can be obtained

Positionally dependent ^(15)N fraction factors in the UV photolysis of N_2O determined by high resolution FTIR spectroscopy

Positionally dependent fractionation factors for the photolysis of isotopomers of N_2O in natural abundance have been determined by high resolution FTIR spectroscopy at three photolysis wavelengths. Fractionation factors show clear 15N position and photolysis wavelength dependence and are in qualitative agreement with theoretical models but are twice as large. The fractionation factors increase with photolysis wavelength from 193 to 211 nm, with the fractionation factors at 207.6 nm for ^(14)N^(15)N^916)O, ^(15)N^(14)N^(16)O and ^(14)N^(14)N^(18)O equal to −66.5±5‰,−27.1±6‰ and −49±10‰, respectively

Are we saving water? Simple methods for assessing the effectiveness of groundwater conservation measures

Substantial storage reductions by irrigation pumping in many of the world’s major aquifers jeopardize future food production. As a result, new conservation measures are being utilized to reduce pumping and extend aquifer lifespans. The key question is how effective are these practices in attaining true water conservation (i.e., water use reduction) for a given area? Relationships between pumping and precipitation help provide an answer, as precipitation explains most of the variation in annual irrigation water use for aquifers in semi-arid to sub-humid climates when surface water supplies are limited. Our objective is to utilize correlations between radar precipitation and irrigation groundwater use at a range of spatial scales to assess the effectiveness of conservation approaches in the High Plains aquifer in the central USA. Linear regressions between pumping and precipitation for a conservation area established in 2013 in northwest Kansas indicate that water use and water use per irrigated area were over 27 % less and 25 % less, respectively, during 2013–2021 compared to the same climatic conditions during 2005–2012. Similar regressions found over a 38 % reduction and 23 % reduction in irrigation water use and use per irrigated area, respectively, during 2018–2021 compared to the same conditions during 2005–2017 in a west-central Kansas county with conservation areas. A decrease in irrigated area accounted for most of the difference between these reductions. Higher R2 values after conservation area establishment imply that irrigation tracks precipitation better due to use of soil moisture sensors and other measures as part of increased irrigation efficiency and enhanced water management. The precipitation and water use relationships, which are statistically significant for a wide range of spatial scales, have great potential for assessing the effectiveness of conservation practices in areas with high-quality water use and precipitation data

The first cosmic ray albedo proton map of the Moon

[1] Neutrons emitted from the Moon are produced by the impact of galactic cosmic rays (GCRs) within the regolith. GCRs are high-energy particles capable of smashing atomic nuclei in the lunar regolith and producing a shower of energetic protons, neutrons and other subatomic particles. Secondary particles that are ejected out of the regolith become “albedo” particles. The neutron albedo has been used to study the hydrogen content of the lunar regolith, which motivates our study of albedo protons. In principle, the albedo protons should vary as a function of the input GCR source and possibly as a result of surface composition and properties. During the LRO mission, the total detection rate of albedo protons between 60 MeV and 150 MeV has been declining since 2009 in parallel with the decline in the galactic cosmic ray flux, which validates the concept of an albedo proton source. On the other hand, the average yield of albedo protons has been increasing as the galactic cosmic ray spectrum has been hardening, consistent with a disproportionately stronger modulation of lower energy GCRs as solar activity increases. We construct the first map of the normalized albedo proton emission rate from the lunar surface to look for any albedo variation that correlates with surface features. The map is consistent with a spatially uniform albedo proton yield to within statistical uncertainties

Suite of simple metrics reveals common movement syndromes across vertebrate taxa

ecause empirical studies of animal movement are most-often site- and species-specific, we lack understanding of the level of consistency in movement patterns across diverse taxa, as well as a framework for quantitatively classifying movement patterns. We aim to address this gap by determining the extent to which statistical signatures of animal movement patterns recur across ecological systems. We assessed a suite of movement metrics derived from GPS trajectories of thirteen marine and terrestrial vertebrate species spanning three taxonomic classes, orders of magnitude in body size, and modes of movement (swimming, flying, walking). Using these metrics, we performed a principal components analysis and cluster analysis to determine if individuals organized into statistically distinct clusters. Finally, to identify and interpret commonalities within clusters, we compared them to computer-simulated idealized movement syndromes representing suites of correlated movement traits observed across taxa (migration, nomadism, territoriality, and central place foraging)

Flow-induced dynamic surface tension effects at nanoscale

The aim of this study is to investigate flow-induced dynamic surface tension effects, similar to the well-known Marangoni phenomena, but solely generated by the nanoscale topography of the substrates. The flow-induced surface tension effects are examined on the basis of a sharp interface theory. It is demonstrated how nanoscale objects placed at the boundary of the flow domain result in the generation of substantial surface forces acting on the bulk flow

Radiation modeling in the Earth and Mars atmospheres using LRO/CRaTER with the EMMREM Module

Abstract We expand upon the efforts of Joyce et al. (2013), who computed the modulation potential at the Moon using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft along with data products from the Earth-Moon-Mars Radiation Environment Module (EMMREM). Using the computed modulation potential, we calculate galactic cosmic ray (GCR) dose and dose equivalent rates in the Earth and Mars atmospheres for various altitudes over the course of the LRO mission. While we cannot validate these predictions by directly comparable measurement, we find that our results conform to expectations and are in good agreement with the nearest available measurements and therefore may be used as reasonable estimates for use in efforts in risk assessment in the planning of future space missions as well as in the study of GCRs. PREDICCS (Predictions of radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP, and other solar energetic particles measurements) is an online system designed to provide the scientific community with a comprehensive resource on the radiation environments of the inner heliosphere. The data products shown here will be incorporated into PREDICCS in order to further this effort and daily updates will be made available on the PREDICCS website (http://prediccs.sr.unh.edu). Key Points We model GCR dose and dose equivalent rates in Earth and Mars atmospheres Dose rates are in reasonable agreement with nearby measurements Data products will soon be made available on PREDICCS website

Measurements of galactic cosmic ray shielding with the CRaTER instrument

[1] The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument aboard the Lunar Reconnaissance Orbiter has been measuring energetic charged particles from the galactic cosmic rays (GCRs) and solar particle events in lunar orbit since 2009. CRaTER includes three pairs of silicon detectors, separated by pieces of tissue-equivalent plastic that shield two of the three pairs from particles incident at the zenith-facing end of the telescope. Heavy-ion beams studied in previous ground-based work have been shown to be reasonable proxies for the GCRs when their energies are sufficiently high. That work, which included GCR simulations, led to predictions for the amount of dose reduction that would be observed by CRaTER. Those predictions are compared to flight data obtained by CRaTER in 2010–2011

Current Understanding, Support Systems, and Technology-led Interventions for Specific Learning Difficulties

In January 2019, the Government Office for Science commissioned a series of 4 rapid evidence reviews to explore how technology and research can help improve educational outcomes for learners with Specific Learning Difficulties (SpLDs). This review examined: 1) current understanding of the causes and identification of SpLDs, 2)the support system for learners with SpLDs, 3)technology-based interventions for SpLDs 4) a case study approach focusing on dyscalculia to explore all 3 theme