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The proposed 110-million-gallon reinforced concrete Headworks Reservoir structures are planned by the Los Angeles Department of Water and Power (LADWP) to be part of the water supply system of the City of Los Angeles, and resilience of the water supply system is crucial for continued water supply in the event of a disaster, such as an earthquake. The seismic resilience of the reservoir structure is a function of the cracking and associated leakage that would be expected due to static loading and during the design level earthquake. Evaluation of the seismic deformation of the structure was accomplished utilizing a soil-structure interaction (SSI) model to evaluate performance of the reservoir structure in an earthquake, after the initial design based on standard code-based design procedures. SSI was used to provide information on the structural behavior of the reservoir, and to understand relative movement of inlet and outlet pipelines. In addition, a leak detection system was incorporated into the design. PROJECT DESCRIPTION AND GEOLOGY The proposed Silver Lake Complex Replacement Project consists of the Headworks Reservoir Complex (East and West Reservoirs), a Hydropower Plant to be constructed on approximately 12 acres within the Headworks Spreading Grounds, and a series of new water conveyance pipelines to and around the existing Silver Lake Reservoir (not at the location of the proposed reservoir site). The current proposed location of the reservoir complex including major project components planned are

The Leon Creek Water Recycling Center (WRC) and Dos Rios WRC facilities, owned and operated by the San Antonio Water System (SAWS), treat the majority of wastewater produced by the City of San Antonio. The Leon Creek WRC Interconnect Project (the “Interconnect”) has been planned to allow for the diversion of flows of up to 51-MGD through a new 60-inch pipeline that connects to the new Southwest Bexar Sewer Pipeline (SBSP), which ultimately ties in at the Dos Rios WRC headworks. This project will delay the need for further expansion of the Leon Creek WRC while maximizing SAWS’ current investment in the expansion and rerating of the Dos Rios WRC from 125-MGD to 217-MGD. This project also allows SAWS to shift more of the raw wastewater supply to the Dos Rios WRC, which services the leg of the recycled water system with the highest demand. In 2010, SAWS contracted with CP&Y, Inc. to study and design the Interconnect. PURPOSE The Leon Creek WRC Interconnect to the SBSP consists of the design and construction of approximately 9,350 LF of 60-inch gravity sanitary sewer line that will convey peak flows from the Leon Creek WRC to a tie-in point along the 96-inch SBSP at the Toyota Manufacturing Facility site. The Interconnect will allow the Leon Creek WRC to continue treating flows from the Western Sewershed, up to its existing capacity of 46-MGD average daily flow (ADF) and peak 2-hour flows (P2HF), of 92-MGD. The Interconnect will delay the need for further expansion of the Leon Creek WRC, which is currently required to convey peak flows by diverting peak flows and future flows generated by a growing upstream system to the Dos Rios WRC. The Dos Rios WRC is currently undergoing a phased re-rating, which will allow the Dos Rios WRC to continue providing treatment for the Central and Eastern Sewersheds while handling flows from the Western, Far West, and South Sewersheds. The proposed Interconnect will allow SAWS to maximize the treatment

Often the design, permitting, construction and startup of an in-situ mechanical device in wastewater open channels is not the hardest task — demonstrating its performance against very stringent criteria after installation is a major challenge and may require a very creative design and delivery approach of its own. Most grit removal systems are not tested after installation and if there is a problem, operators find out only after the system breaks down or large quantities of grit are deposited in systems downstream of the grit removal process, affecting the entire wastewater treatment plant. In most instances these deficiencies cannot be rectified until the entire headworks is up for redesign. As a result of unreliable performance of prior (often conventional style) grit removal systems, some municipalities and clients are requesting that the efficacy of new, proprietary grit removal systems be proven either before they are installed or after installation. The testing usually consists of lab testing, pilot testing, field verification or a combination of these. A system that is unable to meet the treatment goals is either replaced or modified, usually at a cost to the supplier. This paper describes the test methods and sampling procedures used to evaluate two grit removal systems installed at two treatment plants in Clearwater, Florida. The work includes pilot testing for assessing the gradation of the incoming grit and in-situ device verification after the installation of the full-scale unit. The results from the testing indicate that using a multi-pronged approach to characterize grit and size treatment systems is an effective way of ensuring that the installed system is capable of meeting the design goals. The paper recommends adopting this test methodology for assessing installed grit removal systems.

The Calgary Bow River Weir Project is intended to remove an existing safety hazard created by an ogee weir, while maintaining the weir’s ability to divert water for irrigation and not increasing upstream flood levels. The river reach downstream of the weir will be transformed into a high water channel and a low water channel, each comprised of multiple pool-and-drop features to provide recreational opportunities for boaters and improve fish passage at the site. Computational fluid dynamics models were developed to evaluate hydraulic conditions of design modifications to HWC Drop #1. In this study, a volume-of-fluid (VOF) model was employed to predict the water surface profile and to assess whether a hydraulic jump would form downstream of the drop structure. The CFD models were validated by comparing CFD results with qualitative and quantitative data collected in the physical models. The comparisons indicated that the CFD models were able to correctly predict hydraulic jump formation immediately downstream of the weir for the existing design, and demonstrated satisfactory hydraulic conditions for the proposed design at flows at which boat passage is expected to occur. This study demonstrated that CFD modeling is a viable tool for predicting flows involving highly deformed water surfaces, such as those associated with hydraulic jumps. Introduction The existing Western Headworks diversion weir (Calgary Weir), located on the Bow River within the City of Calgary, was constructed in 1975 and is operated by Alberta Environment for the purpose of supplying water to the Western Irrigation District (WID). The weir is located within the Inglewood District, adjacent to Pearce Estate Park on the right bank and Deerfoot Trail on the left bank. Left or right refer to directions as seen by an observer looking downstream. A Canadian Pacific Railway World Environmental and Water Resources Congress 2008 Ahupua'a © 2008 ASCE Copyright ASCE 2008 World Environmental and Water Resources Congress 2008: Ahupua'a 2 (CPR) bridge crossing is located approximately 350 m upstream from the weir and Cushing Bridge (17 Avenue) is located approximately 900 m downstream. The headworks facility includes the WID canal intake structure, a three-bay gated sluiceway, a fish ladder and the diversion weir, as shown in Photo 1. a) View looking north (flow is from left to right) b) View looking upstream (CPR bridge and downtown Calgary in background) Photo 1: Calgary Weir on Bow River – Existing Site Although the weir functions well to satisfy the intended purpose of diverting flow to the WID intake, the design of the weir creates a dangerous hydraulic condition that has claimed several lives over the years, and currently represents an impassable barrier to boaters and fish under most flow conditions. A pre-design study was undertaken to determine the feasibility of modifying the weir to allow small boat passage and to eliminate the dangerous hydraulic roller created by the existing structure (Golder, 2003). Other potential benefits include enhanced fish passage, channel restoration, and the creation of a whitewater recreational facility. The preferred alternative involves modifying the existing weir crest and replacing the existing concrete stilling basin with a series of smaller drops and pools to mimic a “natural rapids” in the reach downstream of the weir. It was proposed that the existing island downstream of the weir be raised and extended to create a separate high water channel (HWC), with multiple pool-and-drop features for whitewater recreational use, and low water channel (LWC) for downstream passage of beginner and novice boaters. Two physical models were utilized in developing the proposed design for the project: a “comprehensive model” was constructed at a scale of 1:50 to provide an overall assessment of how the facility will perform; and a “flume model” was constructed at a 1:15 scale to provide better insight into flow characteristics at specific in-channel drop structures (nhc, 2007). Although the proposed preliminary design met the study objectives, various options for filling in the downstream portion of the weir (HWC Drop #1) were conceptually developed, after the physical models were dismantled, to reduce construction costs. Additional modeling was deemed necessary to confirm whether hydraulic conditions remained satisfactory for the proposed modified design, and this modeling was carried out using computational fluid dynamics (CFD) simulations. World Environmental and Water Resources Congress 2008 Ahupua'a © 2008 ASCE Copyright ASCE 2008 World Environmental and Water Resources Congress 2008: Ahupua'a 3 Study Objectives The objectives of the CFD study were to: (i) assess whether possible design modifications to HWC Drop #1 create hydraulic conditions considered satisfactory from a boat passage perspective; and (ii) provide supporting information for assessing the need for additional erosion protection at the downstream end of the weir structure. CFD Model Description The CFD modeling software, FLUENT (version 6.3.26), was utilized to evaluate hydraulic conditions of the possible design modifications to HWC Drop #1. The model reproduced a narrow “slice” of river channel through HWC Drop #1 with simplified upstream and downstream bathymetries selected to be representative of the prototype. The CFD model employed the volume-of-fluid (VOF) model to predict the water surface profile and to assess whether a hydraulic jump forms downstream of the drop structure (FLUENT, 2007). The κ−e turbulence model was used in the numerical calculations of all simulations. The CFD model was capable of predicting the velocity distribution, water surface profile, vorticity, and boundary shear stresses throughout the model extents, which were used to assess the safety of boat passage and the need for additional erosion protection downstream of the weir. Although CFD models cannot be relied upon for the prediction of detailed standing waves in a river, they are capable of predicting the formation of hydraulic jumps (if present). In addition, qualitative data available from the physical models were used to provide guidance in interpreting CFD model results related to such a flow phenomenon. Geometries in the CFD model were comprised of approximately one million computational elements, which are considered sufficient for providing accurate predictions of flow patterns and velocities. Baseline Simulations (Model Validation) CFD model validation was conducted by comparing CFD modeling results for the existing weir and preliminary design to quantitative and qualitative observations on the comprehensive and flume physical models. Table 1 summarizes operating conditions for the two baseline simulations conducted for the existing weir. Table 1: Operating Conditions for Baseline Simulations Discharge (m/s) Unit Discharge Water Levels at Weir (m) Run No. Flow Condition Total River To WID Intake Below Weir (m/s/m) Upstream Downstream 1 Typical summer flow 150 13 137 0.91 1035.

Embankment preloading, in conjunction with prefabricated vertical (PV) drains, was used to accelerate primary consolidation and to eliminate most of the anticipated secondary settlements of the soft clay foundation due to loading from a proposed wastewater treatment plant (WWTP). Subsurface exploration conducted during preliminary design indicated the presence of up to 60-m thick deposit of soft to very soft clay underlying the site. Estimates of settlement due to filling of the existing lagoon and construction of the WWTP indicated that the soft clay deposits will undergo up to 150 cm of settlement. Approximately 80 cm of this settlement was estimated to occur in the first 10 years of the plant operation and an additional 60 cm was estimated to occur during the following 30 years. UP to 19 settlement plates were installed under the embankment fill to monitor the preload performance. The measured settlements were then used to analyze the behavior of the soft clay foundation, and to develop recommendations regarding the time for preload removal and subsequent construction of the proposed WWTP. This paper discusses the results of settlement analyses and highlights the procedure that was used to predict the magnitude and time-rate of settlements based on field measurements. I N T R O D U C T I O N The city of Chewelah is located approximately 75 km northwest of Spokane, Washington along U.S. Highway 395. As a part of its ongoing improvement, the City has proposed the construction of a new wastewater treatment plant (WWTP). The new facility will consist of biological secondary treatment system providing nitrification, a disinfection facility, sludge handling and treatment facilities, headworks, a laboratory building, and related electrical and instrumentation control equipments. The proposed WWTP will be constructed by filling an existing sewage lagoon (called Lagoon #3) by as much as 2 m of soil to bring the grade to the current top elevation (El. 500 m) of the perimeter dikes. The lagoon covers and area of roughly 90 m by 135 m (see Figure 1). From the as-built drawings provided by the City, it appears that Lagoon #3 was constructed by building the perimeter dikes 1.5 to 2.4 m above the original ground surface. tProject Geotech. Engr., CH2M Hill, Bellevue, WA; 2Sr. Geotech. Engr., CH2M Hill Inc., Corvallis, OR; 3Project Manager, CH2M Hill Inc., Spokane, WA; 4principal, Campbell Services Group, Spokane, WA; SSr. Geotech. Engr. and Staff Manager, CH2M Hill Inc., Bellevue, WA; 6Senior Geotech. Engr., CH2M Hill Inc., Bellevue, WA; 7President, Drainage and Ground Improvement Inc., Bridgeville, PA

The following paper provides information for understanding the significant parameters that determine the reliability, functionality, and total costs for spillway and headwork gate hoists. The technical information covers the unique situations encountered for spillways and headworks. Specific topics include excessive hoist speed and capacity; advantages of low-efficiency, self-locking equipment; motor selection; controls (remote, local, overload, position, and low tech. vs. high tech.); and wire rope selection and lubrication.