A preliminary hydrologic investigation of Topock Marsh, located in northwestern Arizona, was conducted for the U.S. Fish and Wildlife Service between 1995 and 1998. The study identified the hydrological components of the marsh system, quantified an annual water budget, defined the water quality conditions of the open-water marsh, examined water management concerns, and provided data for a concurrent submersed aquatic vegetation (SAV) study. The water budget tabulated monthly values for all hydrologic components except net ground-water flow, which was determined by difference. The principal components were river inflow (+60,020 ± 1,020 ac-f1), rainfall (+890 ± 40 ac-f1), evapotranspiration (-28,170 ± 940 ac-fl), storage (-980 ± 30) and marsh outflow (-26,860 ± 890 ac-f1). The net ground-water value (-6,960 ± 1,650 ac-f1) suggests that the marsh recharges ground-water. The Refuge also exceeded its diversion and consumptive use entitlement. Water quality conditions were assessed using continuous and discrete sampling methods. Three in-situ devices measured routine water quality parameters (temperature, pH, conductivity, dissolved oxygen, oxidation-reduction potential) for two years. Quarterly water samples (1997-98) from four marsh sites were analyzed for major and select minor ions, and δ¹⁸O- δD values. The continuously monitored parameters exhibited, to varying degrees, temporal (diurnal and seasonal) and spatial variability. The marsh was well mixed and has oxygen levels capable of supporting most aquatic life. Evaporative concentration was the major process controlling major ion chemistry. Isotope data confirmed that the marsh and nearby shallow ground-water derive from a river-water source. The marsh is normally turbid (30 NTU), apparently resulting from the resuspension of detrital material by wind-generated waves. The turbidity values dropped below 5 NTU during the 1996 summer as dense patches of SAV "filtered" the water. Light penetration is probably a limiting factor controlling the distribution of SAV in the marsh. Today's water management plan is the culmination of historical practices, incomplete science, institutional goals, and other constraints. Together these factors have led to relatively static hydrologic conditions in the marsh. Potentially negative consequences can result from the continuance of traditional management, including loss of diversity, accelerated in-filling, and salinization. The Refuge should consider simulating disturbances (e.g., flooding) and developing a more complex water management plan.

Thesis (Ph. D. - Renewable Natural Resources)--University of Arizona, 2001. / Page 189 missing in original volume. There are two pages numbered 190. Includes bibliographical references (leaves 329-334).

The Sierrita Mountains were investigated as a site for the proposed Superconducting Supercollider, which was to be housed in a ring-shaped tunnel more than 80 km (50 miles) in circumference. Geostatistical techniques including kriging were used to interpolate the potentiometric surface of the ground water and quantify its uncertainty along the proposed ring alignment to assess potential dewatering problems, based on the sparse water-level information available. Potential water supplies for the Superconducting Supercollider complex include local and imported good-quality ground water, poorer quality but abundant Central Arizona Project water, and Tucson or Green Valley municipal water. Ground water has the most suitable quality, but its development within the Tucson Active Management Area is restricted by state law.

Project Report / September 1981

No description available.

Post-Miocene fluvial and lacustrine units coristitute the valley fill of the San Pedro Valley, near Redington, Arizona. These sediments are relatively flat lying units deposited on older, deformed sediments, fault blocks of Tertiary volcanics, and erosion surfaces on Precambrian crystalline rocks. The sedimentary sequence is composed of silts, inudstone, sands, gravels, limestone, gypsum, diatomite, and pyroclastic units. Previous investigations have designated these lithologies one unit, the Gila Conglomerate. A recent study in the Mammoth area (Heindi, 1963) subdivided the Gila Conglomerate into the Quiburis formation, Sacaton formation and Pleistocene to Recent alluvial deposits. In the present study, this nomenclature was utilized, with a proposed subdivision of the Quiburis formation. Detailed mapping of the lithologic units indicate a lateral facies change within the Quiburis formation0 The conglomeritic member of the Quiburis formation interfingers with a central, fine-grained member, and the names Tres Alasnos, and Redington are proposed for these units. The age of the Quiburis formation is based on its stratigraphic position, and vertebrate fossils. The Qulbuns ovenlies tilted sediments containing Miocene fauna, and its upper portions contain fauna which have been assigned a middle to late Pliocene Age. The Sacaton formation was deposited on an erosion surface in the Quiburis in late Pliobene to early Pleistocene time; it was then entrenched and local, middle to late Pleistocene lacustnine units were deposited in the drainage pattern. Fresh water mollusks, horse and mammoth remains are present in the lacusbnine units. The Pleistocene lacustrine units were truncated by late Pleistocene terraces, and degradation proceeded to approximately 80 feet below the present floodplain. Aggradation occurred, to a level above the present floodplain, as attested by prehistoric hearths buried in river sediments, above the present stream gradient. Since 1880 the San Pedro River has begun another period of downcutting. The sedimentary deposits control the movement of ground water in the valley. Two hydrologic systems are present; a shallow water table system in the floodplain and river channel area, and an artesian system at 630- 1,200 feet below the valley floor in the northern portion of the study area. It is believed that deformed, pre- Miocene sedinentary units provide the source of recharge to the artesian system. Detailed mapping of the sedimentary units reveals a meandering central trough of the ancestoral San Pedro River. The contact between the Redington and Tres Alamos members of the Quiburis formation indicate the meander pattern, and its control by bedrock outcrop. Structural activity continued through Pliocene time, and is represented by north trending normal faults. Minor slump structures and small reverse faults are present in the Redington member of the Quiburis formation. A site survey, carried out during the field mapping, resulted in the location of nineteen archaeological sites. The sites range from preceramic Desert Culture to Salado and probably to later cultures such as the Apache. Older sites are peripheral to the valley axis, with more recent sites concentrated along the river. It appears that geologic-hydrologic factors controlling site location are: water sources; agricultural or gathering areas; quarry, or source material sites; and vantage points.

A gravity station network was established over the Tucson Basin on a nominal one mile spacing for the purpose of determining major hydrologic boundaries. Gravity data were supplemented by magnetic, seismic, and borehole geophysical data. Gravity data reveal a marked linearity of pattern which in general correlates with structural trends previously noted in the area. Based on surface geological data, radiometric dating, and the present survey, it is suggested that the Tucson basin began to form in mid-Tertiary time under tensional stresses. As the circum-basin mountain blocks rose, the Tucson basin was gradually filled by the Pantano formation and its equivalents. Around the margins these were alluvial fan deposits which graded laterally into each other and into playa deposits in the central basin. During the Pliocene Epoch this pattern of internal drainage was disrupted and Pantano deposition ended with the inception of a period of erosion. Deposition of later sediments coincided with external drainage and throughflowing streams. The late-Tertiary and Quaternary sediments probably have been faulted to a minor degree by continuing movement along basement structures or by differential compaction over basement topography. The extent to which this affects groundwater gradients is a function of the percentage of coarse material in the aquifer. Further complications in development of these upper aquifers may be due to igneous dikes and to buried glide blocks of relatively impermeable sediments. The Pantano aquifers are probably broken into relatively small, autonomous hydrologic units by near-vertical fault systems. During this study two new applications of geophysical data were used to analyze basin hydrology. Using Gauss' Theorem the total mass deficiency of the basin was determined and from this a total water content of 129 cubic miles was calculated. The second application involved the use of a borehole density log to calculate the aquifer storage coefficient and revealed a probable value of 0.05, much lower than previously estimated.

Integrated geophysical methods, in combination with available well and geologic data, were used for the purpose of defining the subsurface hydrologic and geologic conditions beneath the Walnut Gulch Experimental Watershed and its peripheral area near Tombstone, Arizona. The 58-square mile watershed, within the 290-square mile area covered by portions of this study, was chosen by the U. S. Department of Agricuiture for intensive research relating to the water and sediment yields from a semiarid range land watershed, Surface geology of the watershed reveals an alluvial fandike area between igneous intrusive and sedimentary rocks that support the Tombstone gills o the southwest and the Dragoon Mountains on the northeast, An interface between the Cenozoic alluvium and volcanic rocks, and the igneous intrusive and sedimentary rocks which are noted as the basement complex, was based on velocity determinations from several seismic refraction profiles, and density determinations of 127 surface samples from 75 sites in 19 different formations, Average values of 2.26 gm/cm3 (grams per cubic centimeter) for the Cenozoic alluvium and volcanic rocks and 2.65 gm/cm3 for the intrusive igneous and sedimentary rocks established a density contrast across the interface of 0.39 gm/cm3, A network of 360 gravity stations established over the watershed and its peripheral area aided in defining configuration of the basement complex, provided depth approximations of the alluvium, and controlled the bearings for subsequent seismic traverses. Magnetic profiles over deep, alluvium-filled areas and the surrounding exposed bedrock was postulated to be useful in deducing source areas and depositional patterns within the alluvium. Structural control of groundwater flow to the northwest was suggested through a combined study of dominant trends on the gravity and magnetic maps. A gravity profile north of the watershed across the largest negative anomaly, with the regional gradient removed, was interpreted as an alluvium-filled graben having a width of ten miles, and a depth of 3500 feet east of its center. Toward the southeast, several parallel gravity profiles indicated a decrease in width and depth of the structure. A total of 54 seismic refraction profiles, aggregating a length of 120,000 feet of in-line seismic profiling, was conducted in 13 areas, Velocities derived from reversed seismic profiles, and profiles conducted over outcrops, averaged 2200 feet per second for channel fill, 5000 feet per second for unconsolidated alluvial deposits, 8800 feet per second for conglomerates, and depending on the particular unit, 12,300 to 15,600 feet per second for basement-type rocks. Mapping of the water table in many areas revealed depths from near zero at the confluence of Walnut Gulch and San Pedro River, to 475 feet in the central portion of the watershed. The accuracy of predicting the depth to either groundwater or basement was ± 6 percent, while that for groundwater alone was ± 10 percent. Analysis of the timedistance data, and correlations with surface geology, grayity, and well data provided a basis for the interpretation of the hydrogeology and recent alluvial history. Finally, a new application of velocities was used in this study to analyze a part of the hydrologic cycle. Based on 23 pairs of observation, a prediction equation was derived through linear regression analysis of density versus velocity. Using seismic velocities, the prediction equation, and relationships between density and porosity, areas of maximum transmission losses within the channel were estimated.

Riparian forests, which support rich biological diversity in the North American southwest, have experienced a sharp decline in the last century. The extent of this decline has been estimated to range from 70% to 95% across the southwest (Johnson and Haight, 1984). The principal components of riparian forests which sustain a broad spectrum of species and describe the overall health of a system are cottonwoods (sp. Populus) and willows (sp. Salix). The importance of cottonwoods is aptly described by Rood et al (1993): "....these trees provide the foundation of the riparian forest ecosystem in semi -arid areas of western North America. Unlike wetter areas to the east and west, a loss of cottonwoods in these riparian areas is not compensated through enrichment from other tree species. If the cottonwoods die, the entire forest ecosystem collapses." Cottonwood and willow species are adversely affected by anthropogenic influences ranging most prominently from the introduction of regulated flows via dams to agricultural clearing, water diversions, livestock grazing, and domestic settlement. These influences effectively alter the system hydrology that the forests rely upon. As the widespread destruction of these forests and the associated irreparable damage to endangered species habitat has come into clear view in the past decade, research efforts have focused upon identifying the ecological needs of riparian systems. The potential of modifying such systems to soften the human impact upon them, in effect presenting further alterations on a hydrologic system to return it to its natural regime, is another component of the research on riparian systems. The Bill Williams River riparian corridor, near Parker, Arizona (Figure 1.1), contains the last extensive native riparian habitat along the lower Colorado River (BWC Technical Committee, 1993). This unique resource was established as the Bill Williams River Management Unit, Havasu National Wildlife Refuge in 1941 and covers 6105 acres along the lower 12 miles of the Bill Williams River (Rivers West, 1990). The Bill Williams Unit is currently managed by the U.S. Fish and Wildlife Service of the U.S. Department of Interior. The U.S. Fish and Wildlife Service also funded this research effort. The lush vegetation corresponding to the wetland conditions along the valley floor sharply contrast with the Sonoran desert landscape of the upper valley walls creating a magnificent picture. The Management Unit terminates at Lake Havasu, which forms the confluence of the Bill Williams and Colorado Rivers. The system provides habitat for a wide variety of species, many of which are endangered or state- listed species, including habitat for neotropical migratory birds. This habitat has undergone serious degeneration during the past quarter century. The recruitment of cottonwood and willow trees has been fatally interrupted by anthropogenic encroachment in the form of the construction of Alamo Dam in 1969 at the head of the Bill Williams River and commercial development along the River.

No description available.