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Hydraulic jacking is a serious threat to concrete spillway chutes, demonstrated by the catastrophic spillway chute failure at California's Oroville Dam in 2017. To improve the understanding of uplift pressure and joint flow developed at open, offset joints and enable design and evaluation of anchors, drain systems, and joint remediations that could help prevent such failures, laboratory tests were performed in a supercritical flume furnished with a model joint where the gap width to offset height ratio was varied over a 725∶1 range. The tests included measurement of boundary layer velocity profiles approaching the joint. Uplift pressures were normalized to the velocity head near the boundary, which is related to the depth-wise velocity profile exponents determined in the experiments and can be estimated for field applications from the chute friction factor. The normalized uplift varies with the joint aspect ratio and the flow depth to offset height ratio. The new relations reduce the uncertainty of modeled uplift pressures by a factor of 2.87 over previous methods. Example applications demonstrate practical upper limits for potential uplift pressure. Subsequent articles will address discharge into offset joints, the dissipation of uplift via drainage, and the effect of different methods for remediating existing offsets to reduce uplift. Practical Applications: Concrete spillway chutes develop cracks and must necessarily be constructed with joints, both of which are prone to displacement over time that may create offsets into the flow. Flow striking such offsets is brought suddenly to rest, similar to a pedestrian tripping on a sidewalk crack. The local stoppage of flow at the offset creates dangerously high pressures that can be injected into the foundation, leading to erosion beneath the slab and potential uplift failure, often called 'hydraulic jacking'. This mechanism has caused several notable failures including the Oroville Dam spillway in 2017. Protection against such failures is usually provided by a combination of the weight (thickness) of the slab itself, anchors that hold the slab down, and subsurface drains that reduce the buildup of pressure. This paper provides experimentally based equations for predicting uplift pressure to enable effective design of new spillways and evaluation of existing spillways. The new equations are significantly more accurate than previous methods because they account for the roughness of the chute surface and the reduced flow velocity near the boundary. Subsequent papers will address flow rate through joints, pressure dissipation by drainage, and methods for treating existing offsets to reduce potential uplift. [ABSTRACT FROM AUTHOR]

This paper presents a laboratory investigation on the use of construction demolition waste in poor clayey soil to improve its strength and drainage characteristics. Various laboratory tests such as differential free swell, Atterberg's limits, compaction, unconfined compressive strength (UCS), California bearing ratio (CBR), and permeability have been conducted on un-stabilized and Construction Demolition Waste (CDW) stabilized clayey soil. The outcomes revealed that the addition of CDW in poor soil reduced both maximum dry density and optimum moisture content. The UCS, CBR, and permeability got improved on adding optimum content of CDW in poor clayey soil. The secant modulus also increased on addition of the CDW in virgin soil. The regression analysis performed for different tests showed good agreement of laboratory results with predicted values. Thus, it can be revealed that using CDW in stabilization of poor clayey soil will not only solve the problem of its disposal but will also be cost effective and protect the environment. [ABSTRACT FROM AUTHOR]

Flood-induced moisture damage of flexible pavements is a serious concern for many road authorities. Reports from several studies confirm the significant structural damage that is caused by flooding on pavements. In general, there is a consensus to design and construct roads that are resistant to flooding. Simultaneously, the concept of resilience has gained popularity – frameworks and specifics are being developed to make civil infrastructure components resilient to natural and manmade disasters. This study provides a framework for quantitatively assessing the resilience of flexible pavements to flooding. The different interlinked steps consist of utilising unsaturated flow through the different layers to estimate drainage, interpretation of the results in terms of stiffness of the relevant layers, estimation of the impact of the change in stiffness on the overall structural condition of the pavement and then translating that change to a resilience index. The paper provides an illustrative example of such an estimation of resilience for a pavement. The results demonstrate the need for providing base course materials with appropriate gradation to ensure adequate hydraulic conductivity, and/or thicker surface layer, to avoid a reduction in service quality and loss of resilience for an extended period of time, in flood-prone areas. Abbreviations: CBR: California bearing ratio; D60: diameter corresponding to 60% passing in results of sieve analysis; FE: finite element; FWD: falling weight deflectometer; HMA: hot-mix asphalt; keff: effective hydraulic conductivity; ksat: saturated hydraulic conductivity; MEPDG: mechanistic empirical pavement design guide; MR: resilient modulus; MRopt: optimum resilient modulus; Q (t); Q: quality; RL: loss of resilience; R: Resilience; S Saturation; SNCratiof: post and pre-flood modified structural numbers (SNCs); SWCC: soil–water characteristic curve; wPI: percentage passing No. 200 sieve × plasticity index. [ABSTRACT FROM AUTHOR]

In order to rigorously examine near surface, field to field interactions between irrigation management regimes and a shallow fluctuating water table, an enhanced deforming finite element (DFE) model was recently developed. The enhanced DFE model, through a process of iteration within each time step, avoids making common assumptions regarding the changing geometry of an aquifer free surface. This paper demonstrates the usefulness and effectiveness of the model by employing it to an irrigated region in the western San Joaquin Valley, Calif., where shallow subsurface tile drains have been installed to control shallow water tables. By virtue of the problems created by the need to dispose off the drainage water, this region has been the focus of several important regional scale modeling exercises, which have evaluated the utility of management strategies, such as source control, groundwater pumping, and land retirement. By refining the focus of the analysis, the enhanced DFE model is found to be able to show that both sources control and managed pumping could be more effective drainage control strategies than predicted based on the results of regional models. [ABSTRACT FROM AUTHOR]

Saline-sodic (4 < EC[dS/m] < 30; 10 < SAR < 40) drainage water can be used to irrigate crops that are moderately sensitive, moderately tolerant and tolerant to salinity. However, in order to be sustainable, particular attention is required towards crop selection, control of soil salination, and crop and soil management to maintain soil permeability to water and air. Potential negative impacts of B, Mo and Se on crop yields, forage quality and wildlife also must be taken into account and, if necessary, mitigated. The focus of this paper is the California experience, along the Westside San Joaquin Valley (WSJV), related to these concerns. [ABSTRACT FROM AUTHOR]

Comments on a study about the liquefaction-induced damage and remediation in Redondo Beach King Harbor, California during the 1994 Northridge earthquake. Use of Seed and Booker's design charts for evaluation of secondary benefits of drainage provided by the stone columns; Analysis methods for drainage columns; Comparison of design methods. INSET: Closure.

Communities in the U.S. fund stormwater management programs to reduce flooding and improve and protect water quality. Few studies have attempted to quantify municipal storwmater management expenditures. This task is important given efforts to meet increasing water quality standards and develop new revenue sources. The purpose of this study was to evaluate trends in municipal stormwater management expenditures across the state of California. The study identified and compiled publicly-available data on reported stormwater expenditures (spending) and budgets for local governments in California. Data were extracted from annual reports for over 160 public agencies. A standardized rubric of activities was developed and used to create a first-of-its-kind database of municipal stormwater budgets and expenditures. The results indicated that there is over $700 million in annual municipal stormwater spending, but this total does not represent all spending due to gaps in publicly-available data. Counties and flood control districts often have the largest total expenditures in a region, but in aggregate cities reported more spending statewide. Available data are not sufficient to adequately evaluate whether current spending meets regulatory requirements. Additionally, publicly-available data are inconsistent across geographic regions regulated by different agencies. The analysis offers a template for improved cost reporting of stormwater programs in U.S. municipalities, which can help answer key questions such as the sufficiency of current funding. Future research can use the method to evaluate spending in other states and regions, evaluate trends over time to improve outcomes, and refine the spending categories based on examples from other states. [ABSTRACT FROM AUTHOR]

Soils in the San Joaquin Valley of California have been a source of selenium (Se) release through dissolution into agricultural drainage, requiring treatment before discharge to the environment. A full-scale primarily anaerobic, granular activated-carbon (GAC) bioreactor with an empty bed contact time ranging from 3.4 to 5.0 h was fed 757 L/min of second-pass agricultural drainage water (ADW) at the San Luis Demonstration Treatment Plant (SLDTP) in Firebaugh, California, for 1,062 days. This study summarized startup of an actual water treatment plant with a process scheme that had never been designed or operated at this scale. ADW nitrate (NO3−) and dissolved oxygen (O2(aq)) concentrations largely dictated the externally dosed carbon (EDC), or glycerin dose, which served as the electron donor to achieve selenate (SeO42−) reduction to elemental Se (Se0). Total Se (SeT) influent concentrations between 111 and 332 μg/L were treated to average effluent SeT concentrations of 7.4 μg/L across the bioreactor. Bioreactor effluent SeT concentrations were further reduced across a downstream ultrafiltration membrane system (UFMS) to an average permeate SeT concentration of 2.9 μg/L. It was determined that most of the SeT removed from the ADW was retained on the bioreactor GAC and was not amenable to removal through backwashing, rendering it hazardous waste by both California and federal standards. Removal of other trace metals such as chromium and uranium were investigated. [ABSTRACT FROM AUTHOR]

This study uses five years of field data from the Land Retirement Demonstration Project located in western Fresno County of California to develop a comprehensive theoretical and numerical modeling framework to evaluate the specific site conditions required for a sustainable land retirement outcome based on natural drainage. Using field data, principles of mass balance in a control volume, the HYDRUS-1D software package for simulating one-dimensional movement of water, heat, and multiple solutes in variably-saturated media, and a model-independent parameter optimizer, the processes of soil water and solute movement in root zone and deep vadose zone were investigated. The optimization of unsaturated soil hydraulic parameters and downward flux (natural drainage) from the control volume against observed vadose zone salinity levels and shallow groundwater levels yield difficult to obtain natural drainage rate as a function of water table height within the control volume. The results show that the unsaturated soil hydraulic properties and the downward flux from the soil profile are the critical parameters. A “natural drainage approach” to sustainable land management for drainage-impaired land is proposed. With this approach it is feasible to design a sustainable land use regimen for drainage-impaired lands in general and retired lands in particular. [ABSTRACT FROM AUTHOR]

Presents a study which considered the retirement of land from agricultural production as a means of reducing the volume of subsurface drainage generated in the Western San Joaquin Valley, California. Conflict between food production and ecosystem health echoes; Conceptual model of land retirement; Characteristics of deforming finite element (DFE) model; Assumptions in DFE transect model.

We propose a novel way to measure and analyze networks of drainage divides from digital elevation models. We developed an algorithm that extracts drainage divides based on the drainage basin boundaries defined by a stream network. In contrast to streams, there is no straightforward approach to order and classify divides, although it is intuitive that some divides are more important than others. A meaningful way of ordering divides is the average distance one would have to travel down on either side of a divide to reach a common stream location. However, because measuring these distances is computationally expensive and prone to edge effects, we instead sort divide segments based on their tree-like network structure, starting from endpoints at river confluences. The sorted nature of the network allows for assigning distances to points along the divides, which can be shown to scale with the average distance downslope to the common stream location. Furthermore, because divide segments tend to have characteristic lengths, an ordering scheme in which divide orders increase by 1 at junctions mimics these distances. We applied our new algorithm to the Big Tujunga catchment in the San Gabriel Mountains of southern California and studied the morphology of the drainage divide network. Our results show that topographic metrics, like the downstream flow distance to a stream and hillslope relief, attain characteristic values that depend on the drainage area threshold used to derive the stream network. Portions along the divide network that have lower than average relief or are closer than average to streams are often distinctly asymmetric in shape, suggesting that these divides are unstable. Our new and automated approach thus helps to objectively extract and analyze divide networks from digital elevation models. [ABSTRACT FROM AUTHOR]

Within a wide range of best management practices for stormwater management in urban areas, there has been an increasing interest in source control measures. Source controls such as low-impact development (LID) techniques are potentially attractive as retrofit options for older developed areas that lack available land to implement conventional measures such as stormwater management ponds. Hence, distributed urban drainage models requiring detailed representation of developed drainage areas should be developed to accurately estimate the benefits that LIDs may provide. This study (1) presents a two-stage classification process on a high-resolution WorldView-2 image, and (2) demonstrates how to use the extracted land cover information in the subsequent hydrologic modelling and assessment of different LIDs’ performance. The proposed two-stage classification method achieved an overall accuracy of 80.6%, whereas a traditional pixel-based achieved 68.4% in classifying the same urban area into six land cover classes. From the classification results, the hydrologic properties of micro-subcatchments were imported in the United States Environmental Protection Agency Storm Water Management Model to assess the performance of LIDs. A reduction of run-off volume 18.2% and 37.1% was found with the implementation of porous pavement and bioretention, respectively, in a typical low-rise residential area located in the city of San Clemente, California, US. The study demonstrates the use of high-resolution remote sensing image to aid in evaluating LID retrofit options, and thus benefits in situations where detailed drainage area information is not available. [ABSTRACT FROM AUTHOR]

Salinization is a global problem, including in California, USA, where over two million hectares of irrigated lands have deteriorated due to salt loading. Because of freshwater shortage, some farmlands are also irrigated with agricultural drainage water, which further exacerbates the salinization process. With the objectives of rapidly quantifying spatial and temporal progression of salinization and identifying yield potential for a high-value crop, we conducted 2-year salinity surveys in a salt-affected farm in California by utilizing a dual dipole electromagnetic induction technology (EM38). The EM-predicted conductivity (EC) was consistent with the ground-truth soil data EC and increased with depth. About 50 and 25 % of the EC data in moderately (A) and severely (B) affected salinity zones surpassed 500 and 1000 mS m levels, respectively. In the northern part of B, up to 70 % samples remained within 500-1000 mS m range. There was eastbound salt loading in the northern and southern parts of A. Rhizosphere salinity showed spatial dependence up to 500 m lateral distance. The shifts in salinity could be due to dispersion and leaching of solutes. High crop yield reduction was estimated in the southwestern and northeastern parts of the field that had typically elevated EC. Around 43 % surveyed area was conducive to attaining 80 % of full yield potential, and the central part of the field was determined to be most suitable for crop growth. Coupling of EM results with production values indicated that under elevated saline condition, it would be feasible to grow a high-value tomato crop. [ABSTRACT FROM AUTHOR]

Estimates of groundwater volumes available in semiarid regions that rely on water balance calculations require the determination of both surface to groundwater lag times and volumes from irrigation or rainfall initiated recharge. Subsurface geologic material hydraulic properties (e.g. hydraulic conductivities, water retention functions) necessary for unsaturated flow modelling are rarely available as are the instrumented field tests that might determine such lag times. Here we develop a simple two-parameter (specific yield, Sy, and pore-size distribution index, λ), one-dimensional unsaturated flow model from simplifications of the Richards equation (using the Brooks-Corey relationships) to determine lag times from agricultural deep drainage associated with the irrigation of alfalfa hay and various row crops in the Antelope Valley of California, USA. Model-predicted lag times to depths of 85 m bgs (below ground surface) were similar to that measured in a 2-year ponded recharge field trial, slightly overestimating that measured by approximately 15% (0.51 vs 0.44 years). Lag time estimates were most sensitive to estimated deep percolation rates and roughly equally sensitive to the model hydraulic parameters. Generally, as subsurface material textures coarsen towards larger Sy and λ values for all Sy >10%, lag times progressively increase; however, at Sy <10%, lag times decrease substantially suggesting that particular combinations of Sy and λ values that may be associated with similarly textured materials can result in the prediction of different lag times for Sy approximately 10%. Overall, lag times of 1-3 years to a depth of 69 m bgs were estimated from deep drainage of agricultural irrigation across a variety of irrigation schedules and subsurface materials. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Agroforesty systems, which are recommended as a management option to lower the shallow groundwater level and to reuse saline subsurface drainage waters from the tile-drained croplands in the drainage-impacted areas of Jan Joaquin Valley of California, have resulted in excessive boron buildup in the soil root zone. To assess the efficacy of the long-term impacts of soil boron buildup in agroforesty systems, a mathematical model was developed to simulate non-conservative boron transport. The developed dynamic two-dimensional finite element model simulates water flow and boron transport in saturated–unsaturated soil system, including boron sorption and boron uptake by root-water extraction processes. The simulation of two different observed field data sets by the developed model is satisfactory, with mean absolute error of 1.5 mg/L and relative error of 6.5%. Application of the model to three different soils shows that boron adsorption is higher in silt loam soil than that in sandy loam and clay loam soils. This result agrees with the laboratory experimental observations. The results of the sensitivity analysis indicate that boron uptake by root-water extraction process influences the boron concentration distribution along the root zone. Also, absorption coefficient and maximum adsorptive capacity of a soil for boron are found to be sensitive parameters. [ABSTRACT FROM AUTHOR]

Beheaded west-flowing drainages are identified in the northern Sierra Nevada west and north of the Lake Tahoe Basin. These include the canyons of the modern South Fork American River, the Rubicon River, the South Yuba River and their tributaries. These drainages were beheaded, east-side-down displacements along faults of the Tahoe-Sierra frontal fault zone as Cenozoic normal faults encroached into the Sierra Nevada block about 2.5-3 Ma. Most major Sierran passes in this region are wind gaps or water gaps formed by beheading, and include Carson Pass, Echo Summit, Aloha Pass, Velma Lakes Pass, Miller Creek Pass, Five Lakes Pass, Donner Pass and Euers Saddle. The Carson Range represents a remnant of the former Sierran crestal region, and may have formerly attained elevations between 3.6 and 4 km. Possible remnants of the beheaded west-flowing Sierran drainages occur as major passes in the Carson Range and include passes at Big Meadows, Luther Pass, Armstrong Pass, Star Pass, Daggett Pass, Spooner Summit and Tahoe Meadows. Several possible remnants of a tributary of the modern Rubicon River, Five Lakes Creek, are preserved in mountainous areas along the north edge of Lake Tahoe. Carson Range faults beheaded many of the drainage remnants, indicating that the ∼3 Ma Sierran drainage divide lay somewhat east of the present crest of the Carson Range. Speculative reconstructions of the former South Fork American, Rubicon and South Yuba drainages, along with other regional data, provide constraints on timing and rates of uplift, tilting and normal faulting, and support recent concepts about mechanisms of late Cenozoic Sierran uplift. [ABSTRACT FROM AUTHOR]

Abstract  Larval series of the Santa Ana sucker, Catostomus santaanae (Federally Threatened), arroyo chub, Gila orcutti (California Species of Special Concern), and Santa Ana speckled dace, Rhinichthys osculus (California Species of Special Concern) are described from wild-caught specimens from the Los Angeles and Santa Ana river drainages. Santa Ana sucker larvae are elongate, having 41–46 myomeres and a distinctive paired-triangle patch of melanophores over the midbrain. Melanophores present on the snout, dorsal body, lateral midline, dorsal gut, postanal ventral body, and caudal fin. Preanal length 74–79% in body length (BL), typical of catostomids. Arroyo chub larvae relatively deep-bodied, 36–39 myomeres, and a heart-shaped patch of melanophores over the midbrain with a line of melanophores trailing posteriorly. Heavy pigment present on the snout, lower jaw, dorsal body, lateral midline, gill arches, dorsal gut, postanal ventral body, and caudal fin; short preanal length of 65–72% BL, typical of native North American cyprinids. Santa Ana speckled dace are similar to arroyo chub except for having less pigment on the ventral gut, large distinct melanophores on the ventrolateral caudal peduncle, a wedge-shaped patch of midbrain melanophores with no distinct line trailing posteriorly, and lateral midline melanophores that do not extend anteriorly. These three species often occur together and with nonnative cyprinids. Characters distinguishing them from other local larvae, including southern fathead minnow, Pimephales promelas confertus and red shiner, Cyprinella lutrensis, are discussed with their habitat preferences. [ABSTRACT FROM AUTHOR]

Irrigation with saline water has a positive impact on some quality indices of processing tomatoes, but with concomitant reductions in output quantity. This article studies the impact of the trade-off between these two factors on optimal water management under waterlogging and costly drainage-disposal conditions. The focus is on the content of total soluble solids as a quality measure affecting prices paid by California processors to tomato growers. A function relating quality to water and salinity applications and a quality hedonic-price function are estimated and introduced into a static, field-level mathematical programming model. The model calculates optimal water management under environmental regulations associated with drainage disposal in California. Findings indicate that only when the quality effect is taken into account does blending fresh surface-water with saline drain-water become an optimal strategy. Management and policy implications on the regional scale are discussed. [ABSTRACT FROM AUTHOR]

Highly productive, irrigated agriculture can be found in California's Central Valley made up of the Sacramento, San Joaquin, and Tulare Lake basins. High water tables throughout much of the San Joaquin and Tulare Lake portions of the Valley threaten this highly productive region. Due to topographic and environmental constraints much of the region is currently without drainage. In 1990 State and Federal government agencies combined to produce a report that outlined possible steps to deal with the drainage issue. These steps included: 1) Source control (practices to reduce the amount of drainage water); 2) Drainage reuse; 3) Evaporation systems; 4) Land retirement (cease irrigation); 5) Groundwater management; and 6) Discharge to the San Joaquin River. General background information to the history and hydrology of the Valley as well as a discussion of the feasibility and constraints of providing drainage by discharging drain water to the San Joaquin River are presented. In addition a general discussion of the technical and political limitations of providing drainage in the River are discussed. [ABSTRACT FROM AUTHOR]

Constructed evaporation ponds are being utilized for disposal of saline subsurface drainage waters in San Joaquin Valley, California. These terminal evaporation ponds are located in hydrologically closed basins and/or regions with no surface drainage out of the valley. The saline drainwaters disposed into the ponds are sodium-sulfate or sodium-sulfate-chloride type waters and upon desiccation produces mirabilite and halite. The drainwaters contain excessive levels of trace elements from geochemical origins. The trace element of most concern, is selenium because it bioaccumulates in the aquatic food chain and causes death and deformity of waterbirds attracted to the pond environment. At the present, the only economic drainwater disposal option in the southern. portion of the valley is evaporation ponds. The operation of these ponds is heavily regulated by waste discharge requirements to reduce and mitigate wildlife impacts. A case study on evaporation ponds and bird usage from a drainage district illustrates the extensive monitoring and mitigation required. The prognosis is evaporation basins will be needed for the foreseeable future unless breakthroughs occur in economic and effective drainwater treatment and drainwater reuse options. [ABSTRACT FROM AUTHOR]

Evaluates the impact of irrigation and drainage policies on agricultural sustainability in central California. Average salinity of water deliveries; Restrictions on drainage water discharge; Improvements in water management; Reductions in drain water volume.

Focuses on the riparian forests in Sacramento Valley, California. Plant associations consisting the pristine vegetation of the valley floor; Elimination of marsh vegetation from the valley by drainage and flood control; Conduciveness of the climate to flooding.