Confluence Water Resource Planning Model User Guide Version

Transcription

1 Confluence Water Resource Planning Model User Guide Version Confluence is a modeling system that is designed to meet the water resource planning needs of wholesale and retail water providers. Those needs are diverse, and Confluence was developed with this diversity in mind. As questions arise, please contact: Gary Fiske, President Gary Fiske and Associates, Inc. Phone: Fax: gary@fiske-assoc.com PLEASE READ THE FOLLOWING YELLOW-HIGHLIGHTED SECTIONS TO ENSURE A SMOOTH START-UP. 1

2 Minimum System Requirements Windows 95, 98, 2000, XP, NT, or Vista Pentium class processor (at least 1.0 GHz recommended) 128 MB RAM (256 MB with Windows NT) SVGA video 30 MB hard drive space for installation. Installing Confluence To install Confluence, first download the installation file, called Confluence Demo.msi run the file, and then follow the instructions. The installation process generally proceeds very quickly. Notes: It is recommended that you use the default folder (C:\Program Files\Confluence) to store the Confluence model files. You may be asked whether you want to replace an existing system file with one that has an earlier date. Click Keep Existing. Because of Windows Vista security issues, Vista users may need a small additional step in the installation process. A small batch file, named Conf_reg.bat, which is provided along with the Confluence installation package, must be copied to the C:\Windows\System32 folder. After the Confluence installation is complete, the user then must right click this file and choose Run as administrator. If other Vista operating issues arise, please contact us. Opening Confluence To begin using Confluence, open the Confluence.exe file in the folder specified during the installation process. (You may wish to place a shortcut to this file on your desktop.) The model will load and then you must open an input file. Click on either the folder icon in the tool bar or Open Database... in the File menu. In the Choose an Input Database dialog box, locate the folder in which the study you wish to work with is stored and open the input file. (The input file is a MS Access database, and will have a.mdb extension.) The desired database will be opened and the system schematic will appear. (If necessary, the schematic may be enlarged by dragging the lower right-hand corner.) NOTE: The model trial version available for download from the Confluence website includes a sample input data base (Confluence Sample.mdb) that is stored with the data files in the directory C:\Program Files\Confluence\Data. 2

3 Before running the model simulation, it is recommended that you copy the data base to its own folder, but leave a copy in its original location. Then, once the model is opened, open the input file in the new folder, and run the simulation on that file. This will ensure that all of the output files are stored in this unique folder. (See Scenario Management below.) The Confluence User Interface The data for each Confluence study (scenario) are stored in a separate Microsoft Access database. The Confluence Visual Basic User Interface is specifically designed to allow quick and easy viewing and editing of all study variables. The interface also is the place from which the simulation is run and simulation results are viewed. Much of the discussion that follows will focus on how best to use the Confluence interface. Scenario Management Confluence is designed to facilitate evaluation and comparison of multiple resource strategies, each of which will include a variety of supply, infrastructure, conservation, and operational components. Each such study will be defined in its own database which, as described above, is edited from the user interface. Moreover, the simulation results for each study are stored in the same folder in which the input database is stored. Each study should therefore be saved to its own folder. When the user modifies a scenario and wishes to save both the original and modified versions, the latter should be saved to a new folder prior to running the simulation. The locations and hierarchical structure of the folders are up to the user, and should be determined based on logic and convenience. Typically, a water supply planning effort will result in the creation and evaluation of a large number of studies, which in turn will result in a multi-tiered set of folders each of which contains the input database and the most recent simulation results for a particular study. Constructing the System The system schematic can be easily modified as follows: To add a supply source, reservoir, or treatment plant: Right click anywhere on the map. A dialog box will appear. Click : Add Source... Select the type of addition you wish to make, name it and click OK. If you wish to add additional sources or treatment plants, repeat the process. When finished adding sources, 3

4 click Close. Icons for each added source will appear in the upper left. Drag each icon to the location where you would like it displayed. To add a node: Right click anywhere on the map. A dialog box will appear. Click Add Node... A dialog box will appear. Name the node and indicate what type of node it is and click OK. (Connection nodes are simply junctions within the transmission system that do not have any water demands associated with them.) If you wish to add additional nodes, repeat the process. When finished adding nodes, click Close. Icons for each added node will appear in the upper left. Drag each icon to the location where you would like it displayed. To change font size, icons, or colors: Right click anywhere on the map. A dialog box will appear. Click Map Display Options. Specify the changes you wish to make. To change the position of the entire schematic: Right click anywhere on the map. A dialog box will appear. Select Shift Layout and indicate the desired shift. To add transmission: Transmission lines can be added to link pairs of nodes. Click on the arrow symbol on the tool bar or on Transmission; Line Data/Schedule in the Edit menu. A data form appears. For each transmission link you wish to add, select the 2 nodes that are to be linked. You may either specify the characteristics of this transmission line now or later (see instructions below). Click on Close when you have defined your transmission links. They will now appear on the map. To rename or delete nodes or sources: To rename nodes, right click on the node and select Rename. Supplies, treatment plants and reservoirs can be renamed by double clicking on the source and changing the Project Name. Sources and nodes can be deleted by right clicking on the icon and selecting Delete. To resize the map pane: Position the mouse over an edge or corner until the double arrow appears and drag in the direction you wish to resize. Defining System Components The characteristics of each supply source, reservoir, treatment plant, transmission link, and demand node can be readily specified through the user interface. Some of the underlying data (e.g. streamflows, rain on surface, weather-normalized demand, and daily weather-adjustment factors) are not directly accessible through the user interface, but are stored in large text files, which can be easily viewed and edited using a standard text editing application. 4

5 Before discussing how to define the characteristics of each system component, two critical concepts must be discussed, pointers and shadow prices. Pointers The concept of pointers is crucial to understanding Confluence operation. There are many parameters, such as escalation rates, water rights, allocations, reservoir rule curves, etc. which are referenced in many places throughout the interface, and are used repeatedly in the simulation. The most efficient way to invoke such parameters for various purposes is to point to a central cache of data wherever needed. For example, the simulation must know the growth rates through the end of the study period for many variables, including virtually every cost element for each system component. Rather than repeatedly defining escalation rate vectors for what could easily be thousands of components, a set of escalation paths is separately defined and each path is named. Then, each cost element simply points to the name of the appropriate escalation path to define how that element will change over time. Another example of a commonly used pointer is monthly allocations. Many model parameters must be allocated across the months of the year. So, a set of monthly allocations is separately defined and named, and referenced as necessary throughout the interface. There are many other instances in which pointers are used. The manner in which they are defined and used will be discussed below. Shadow Prices and Economic Dispatch A second critical concept is that of shadow prices. In any time step, the way that the available supplies are dispatched is governed by these prices. This allows the dispatch to deviate from one based on the actual economic costs of the supplies. Pure economic dispatch would mean that, in each time step, the model will operate the system to minimize costs. Thus, subject to capacity, volumetric, and other user-specified constraints, the dispatch would seek to meet demand with those supplies which have lower variable operating (running) costs first, and only use the sources with more expensive running costs as necessary. There are many reasons why system operations will be governed by other than this pure economic model. For example: For regulatory, water quality, or other reasons, a water provider may wish to operate a more expensive source before operating a cheaper one. 5

6 For contractual reasons, a particular supply source may only be able to serve demands after the supply from another source is exhausted, even though the latter source is more expensive to operate. The actual operating cost to draw down a reservoir may be very small, but emptying the reservoir midway through a hot, dry summer would likely be an imprudent operating strategy. Likewise, it might be desirable to leave some water in storage in lieu of meeting some demands in one water year, so that stored water can be carried over to meet demands in a subsequent year. All of these rather common examples point to the fact that real-world system operations are often governed by something other than economic costs. Shadow prices allow Confluence to simulate real-world operations, while maintaining virtually complete data-driven flexibility to test different operating approaches. A shadow price is a fictitious cost that can be assigned to supplies, reservoirs, transmission links, and demand nodes. It need bear no relation to actual variable operating costs, and its absolute magnitude has no significance. What is critical are the magnitudes of shadow prices relative to one another. Shadow prices only affect system operations. Confluence cost accounting remain based on actual economic costs. The user will have the opportunity to set many shadow prices as system components are defined. The various applications of shadow prices will be discussed below. Supply and Treatment Plant Characteristics To specify the characteristics of a supply source, reservoir, or water treatment plant, double click on its icon. A multi-tabbed data form will appear that allows specification of all the parameters that describe the source. In all cases, the Base Data tab describes the beginning state of the supply or treatment plant (capacity, operating costs, operating characteristics) at the start of the study period. Following are descriptions of the forms for each type of supply. River Diversions Base Data tab On this tab, the source is linked to a particular demand or connection node. (Each source must be linked to a node. Once that linkage is specified, it will appear on the system schematic.) In addition, this tab specifies the existing diversion capacity, as well as the on-line date and the operating life. The latter 6

7 two parameters provide information on when the source will be taken on and off line. (As long as the useful life of the source extends beyond the planning horizon, the source will be available for the entire study.) This tab also permits the user to specify a percentage Must Run Level which provides a minimum operating level for the source. It also allows definition of various short-run operating parameters. This tab also provides fixed and variable operating cost data. Each cost item is expressed in base year dollars. The base year is specified in the Study Definition Parameters form (see below). Each cost also has a real escalator pointer which references a vector defining the real escalation rates of that cost component. (See below for a description of how to create and edit these pointers.) Also on this tab are check boxes to specify whether production duration curves should be produced and whether the source can be used for reservoir fill. Other items on this tab include pointers which allows the user to vary the capacity or the variable operating cost of the supply, if desired, by month, and a choice of whether the water produced by this source is raw or treated. (This will only affect the color of the connector between the source and the linked node in the system schematic; it will not affect the simulation.) If applicable, the user can also specify a Downstream Project, which permits the user to define a series of two or more linked diversion points, for which the available flow at each diversion point is the flow at the immediate upstream diversion point less the upstream project s diverted volume. The Downstream Project defined on this tab is the diversion immediately downstream of the current project. Stage Data tab Here, the user can add incremental stages to this supply during the study period. The user specifies all capacity, cost, financing, and cash flow characteristics for each stage, as well as the year in which each stage becomes operational. The model will assign default values to any item that is not filled in. Key data items that are not self-explanatory include: Incr FOM. The incremental fixed annual operating & maintenance cost associated with the stage addition, expressed in base year dollars. This is added to the Existing Fixed OM specified on the Base Data tab. Cash Flow Distr. The manner in which the capital cost is distributed across years ending with the Year On Line. Finance Set. A pointer which specifies the manner in which the capital investment will be financed (interest rate and amortization period). 7

8 SDC%, SDC Fin Set. These variables permit the user to specify a portion of the capital cost of a stage addition to be paid for through System Development Charges (SDC) rather than by ratepayers. Incr Reg Compl. This is a qualitative index of regulatory compliance for this supply. See below for a discussion of qualitative indices. Flows, Rights tab This tab includes information on water rights and streamflows. Variables include: Water Rights Type: There are currently three possible types of rights: Flow_Single: A basic set of flow-based water rights that apply to this source. Flow_Joint: A set of flow-based rights which are shared by multiple sources. Dmd_Function: A water right that is triggered by daily demand levels at specified nodes. If the user specifies either a Flow_Single or a Flow_Joint right, then the pointer to that right set is named in Water Rights (Flow). If a Dmd_Function is specified, the pointer is named in Water Rights (Dmd). Streamflow Pointer: Here, the user indicates the name of the streamflow data set that applies to this diversion. This data set is contained in the Daily Streamflows text file. (See below for discussion of external text files.) Note that, in linked diversion set, these flows are added to any flows coming from upstream projects. Instream Reqmts: This field points to a set of instructions relating instream requirements to streamflows. These instructions are accessed through the Edit menu (see below). If desired, the user can also limit production from this source by specifying a Volume Limit and an associated number of years over which this limit applies. (The Confluence default assumption is no volume limitation.) This tab also allows the user to limit the nodes to which water produced by this source can be delivered. To enable this constraint, click on the check box, and then on Modify. Then add or remove nodes/reservoirs as desired. Note that these node-delivery constraints are in addition to the physical system limitations, e.g. transmission or treatment capacity. 8

9 Finally, the user can define a shadow price for this source, along with its real escalation rate. If enabled, this shadow price will govern the dispatch of this source during each model time step. If disabled, the dispatch will be governed by the actual variable operating cost (power + chemical). (See above discussion of shadow prices.) Other Data tab This tab includes various options to constrain the operation of this supply. All of these are accessed through the Edit menu (see below). Operating constraints include: Step Capacity Ptr: These are discrete levels of delivery capacity at which this source is constrained to run. Joint Hydraul Ptr: Hydraulic limitations on maximum production rates that are a function of the operating level(s) of another supply. Turbidity Ptr: A turbidity constraint that forces the supply to be shut down as a function of multi-day rainfall events of particular magnitudes. Flushflow Ptr: A beginning-of-season restriction on source use prior to achieving some threshold level of flushing flow. In addition, the Fixed Cost Alloc pointer allows specification of the manner in which fixed cost components will be allocated to demand nodes, if such an allocation is desired. The tab also allows the user to assign values to various Qualitative Indices for this supply source. Allowable Flow Years: The user is permitted to limit the use of the source to particular hydrologic years (e.g. only in dry years). The years must be separated by commas; ranges of years can be indicated with hyphens. (As described below, historical daily hydrologic flows are specified in an external text file.) The Notes tab is for any notations the user wishes to make about this supply. 9

10 Groundwater Supplies Unlike river diversions, groundwater supplies are not constrained by flows or water rights. Other than this, the data elements to characterize groundwater supplies are identical to those for river diversions. Their arrangement on the data tabs differ slightly. Seasonal Reservoirs Many of the input variables for a surface reservoir are identical to those discussed above. Following are descriptions of those parameters which have not been previously described. Base Data tab Unlike diversion and groundwater supply projects, Confluence considers a surface reservoir a node. Thus, the user does not need to independently specify a node. Base reservoir data not already described includes: Res Type: The user must specify one of three possible types. A normal reservoir is a surface reservoir that is drawn down to meet demands and/or to fill downstream reservoirs. ASR indicates an aquifer storage and recovery project. Flow Aug denotes a reservoir for which the releases are used to augment flow in a designated stream. Total Storage: The total storage capacity of the reservoir. Dead Storage: The portion of the total storage that is inaccessible. The difference between the total storage and the dead storage is the storage capacity that is useable. Prefer Min Storage: Here, if desired, the user may specify a critical storage volume. Confluence will track the frequency of lower storage volumes and report on this in several output charts, but the simulation will be otherwise unaffected. ASR Inject Cost: This variable only applies to ASR projects and indicates the costs, if any, to inject water into the aquifer. Downstream Project: This indicates the downstream reservoir, if any, which receives spills from this reservoir. This tab also includes three check boxes to control the types of outputs to be created for this reservoir. 10

11 Rule Curves, Evap, Streamflow tab On this tab, the user specifies pointers that control the operations of the reservoir. The specific contents of these pointers will be described below. The following pointers are included: Rule Curve Set. A pointer to the set of rule curves and zonal shadow prices which govern the economic drawdown and refill of the reservoir. Rule curves are discussed below. (Rule curves are only applicable to a reservoir that has been identified as Normal or ASR.) Streamflow. The identifier for the daily inflow data set for this reservoir. This data set is contained in the Daily Streamflows text file. (See below for discussion of external text files.) Rain on Surface. The identifier for the historical rain on surface data set for this reservoir. This data set is contained in the Monthly Reservoir Rain on Surface text file. Evaporation. The identifier for the historical evaporation data set for this reservoir. This data set is contained in the Monthly Reservoir Evaporation text file. Vol/Surf Area Curve. The pointer for the volume/surface area curve for this reservoir. These curves are used to calculate rain-on-surface and evaporative losses. These curves can be created and edited from the Edit menu. (See below for full discussion of Edit menu.) Instream Flow Reqt. The identifier for the vector of required monthly instream flows that must be maintained downstream of the reservoir. These requirements are created and edited as water rights on the Edit menu. Instream Flow Loss. The identifier for the losses, if any, that will be reflected in the receipt of spills in the downstream reservoir (if one has been identified). Flow Aug Flow Set. The identifier for the streamflows that will be augmented by releases from this reservoir. (Only applies to a reservoir that has been identified as Flow Aug.) Flow Aug Data. The pointer to the instructions (accessed in the Edit menu) that govern the flow augmentation releases from this reservoir. (Only applies to a reservoir that has been identified as Flow Aug.) 11

12 Other Data tab In addition to allowing the user to specify the nodes to which delivery from this reservoir is constrained, this tab also permits the user to constrain the supply sources from which this reservoir is permitted to be filled. (Note that the source must also allow use for reservoir fill.) Water Treatment Plants For a treatment plant, both an input and an output node must be specified. All other water treatment plant data elements are as described above. Transmission Links To specify the characteristics of any transmission link, click on the Arrow on the tool bar, or on Transmission; Line/Data Schedule on the Edit menu. A Transmission Data grid appears, on which node-to-node transmission links can be created and edited. Data elements include: Link ID. A user-provided name for this link. Node 1, Node 2. These define the two nodes that are linked. Each of these cells allows the user to choose from a list of all demand nodes, connection nodes, and reservoirs. Type. The user must enter either R (raw) or T (treated). This parameter governs only the color of the transmission link in the system schematic. It does not affect the simulation. Year On Line, Oper Life. These define the period during which the link is operational. Capac 1, Capac 2. Capac 1 is the nominal link capacity from Node 1 to Node 2. Capac 2 is the capacity from Node 2 to Node 1. (Note that this nominal capacity can vary as a function of other system parameters, as described below.) Losses, expressed as a decimal. Thus 0.1 means a 10% loss rate on this link. Pump Cost 1, Pump Cost 2, Pump Cost Escalator. Pump Cost 1 is the pumping cost from Node 1 to Node 2. Pump Cost 2 is the pumping cost from Node 2 to Node 1. Both of these are expressed in dollars of the Cost Reference Year which is designated in Study Definition Parameters (see below). Pump Cost Escalator is a real escalation pointer for these costs. 12

13 FOM, FOM Escalator. The annual fixed O&M costs, expressed in costreference-year dollars, and the real escalation pointer for these costs. Capital, Capital Escalator. The capital cost of the link in cost-reference-year dollars, and the real escalation pointer for these costs. Cash Flow Distr. The user can specify pointers which define the distribution of this capital outlay in the year(s) ending with the year prior to the on-line date. Finance Set. Here, the user names a pointer which specifies the manner in which the capital investment will be financed (interest rate and amortization period). Fixed cost allocation allows the user to point to a node allocation vector to allocate the fixed costs of this link to particular demand nodes. Duration curve? The user must indicate whether or not flow duration curves should be produced for the link. Caution: Duration curves add sort time to the model run. Therefore, only select yes for those transmission links for which duration curve outputs are important for the particular study. Include Pump Cost in Acctg? The user can determine whether Confluence will include the pumping cost of each link in its cost accounting. Typically the entry will be Yes. Double clicking on each cell in this column will toggle between yes and no. Regul Compl Index. This is a placeholder for a qualitative assessment of regulatory compliance or any other qualitative attribute of the transmission link that the user wishes the model to track. Additional indices can easily be added. Shadow 1, Shadow 2. The user can specify transmission shadow prices for each direction of flow. These shadow prices are a way to fine tune the model to more closely mimic the manner in which the system will be operated. In most cases, these will be zero. Demand Characteristics Forecasted demand can be defined in one of two ways, internally or externally. Internal demand growth forecasts are defined in the Confluence user interface, and are deterministic. External demand growth is defined in an external text file, can have multiple demand growth paths, and may be defined independently for each class of service in each demand node. The manner in 13

14 which the simulation will sample from the demand paths is defined in the interface, namely in the Demand tab of the Study Definition Parameters form. In either case, the daily demand varies as a function of weather. Daily variation of per-capita (or per-account) internal demand is defined by a functional relationship between demand and current and lagged temperature and precipitation data. The demand in all nodes is governed by this relationship. Daily variation of external demand can differ by node and by class. These relationships are defined in another external text file. Defining demands externally is typically considerably more complex than internal definition, but it allows for a richer and more nuanced analysis of demand variations. Internal Demands The internal demand growth characteristics are accessed by clicking on Demand Data in the Edit menu. This form can also be accessed by double clicking on any demand node. Base Demand Tab This tab is divided into several sections, as follows. Peak-Season: Peak-season demand is computed on a daily basis. For any peak-season day, the demand is the product of that day s weatherdriven per-capita demand and the forecast population total for the study year. (Note that population may indicate number of residents, households, accounts, etc.) The function that computes the per-capita demand is specified on the Int Demand Coeff tab (see below). Growth Pointer. The identifier for the vector of annual growth rates, which specifies the growth of the population through the planning period. Ref Yr population. The starting population to which the growth factors are applied. Calibration set. The identifier for a vector of annual adjustment multipliers which are applied to each computed daily demand in the peak-season. This may be useful, for example, to calibrate the average-weather demands to a separate weather-normalized forecast generated elsewhere. The calibration vectors are created and edited by clicking the Calibration button. 14

15 Off-Peak Season: Off-peak season demands are computed on a monthly basis, and are not weather-driven. Other: Growth Pointer. The identifier for the vector of annual growth rates, which specifies the growth of the off-peak-season demand through the planning period. Monthly Distrib. A pointer which describes the manner in which the total off-peak-season demand is distributed across the months of the off-peak season. Daily demands within each month are assumed to be equal. Ref Yr Season Avg mgd. The starting point for the average seasonal daily demand in the reference year. Demand Reference Year. parameters refer. The year to which starting-point demand Node Allocation Pointer. The identifier for a node-distribution vector that defines the manner in which the demand is distributed across nodes. Climate Change Growth Effects. One of the potential impacts of climate change is to modify population growth rates due to changes in in-migration to and out-migration from the service area. This growth pointer permits the user to define such impacts, which are in addition to the Growth Pointers for the peak and off-peak seasons. (Specification of climate change impacts on per-capita demand will be discussed below.) Subdaily Def and Daily Shapes Tabs Data on both of these tabs define diurnal demand variation. New Large Demand Tab On this tab, discrete demands can be added to designated nodes. Each of these demands is governed by separate growth, node allocation, and monthly distribution schedules. These demands are added to either internally- or externally-defined demands. Node Params Tab This tab includes the following parameters for each demand node: 15

16 Unserved Price, Price Incr, Escalation Pointer. The Unserved Price is a shadow price that is assigned to the least expensive block of unserved demand in the node; the Price Incr is the increment that is successively added to define the shadow price of succeeding unserved demand blocks. These parameters are useful to control the manner in which unserved demand is allocated to nodes. When combined with the shadow prices assigned to reservoir blocks (see above), they can also control the manner in which water in storage is preserved for carryover rather than serving current-year demand. Path Set Pointer. For externally-defined demands, this determines the data set within the Monthly Demand Data external text file which will apply to the particular node. If the path name does not correspond to a set name in the text file, an error message will be generated when the simulation is run. Seasonality Pointer, Weather Effects Pointer. For externally-defined demands, these determine the data sets within the Daily Demand Weather Effects Data text file which will apply to the particular node. Int Demand Coeff Tab It is here that the coefficients of a linear internal demand function are specified. As noted above, this function determines the per-capita or per-account demand. Typically, the coefficients of this function will be developed through a separate demand study conducted by the utility. In the interest of being as general as possible, there are many variables on this tab. The user need not use them all. Blanks will be read as zero. The dependent variable is assumed to be daily per-capita (or per-account) demand in gallons. Following are descriptions of the independent variables: Weather Variables: These variables include current-day and one-, two-, and three-day lagged (i.e. previous days) temperature (in degrees F) and precipitation (in inches). Period Adjustments: These include 12 monthly one-zero (i.e., on-off) variables, which capture monthly additional (or diminished) demand, independent of daily weather. Also included is a one-zero weekday adjustment, which captures any added demand on weekdays as opposed to weekend days. 16

17 Other variables: The coefficient of the Cal Year variable is the number of gallons that demand is expected to change from year to year regardless of weather. A negative coefficient indicates an expected secular decline in per-capita demand; a positive coefficient indicates an expected increase. In addition, there is an Intercept which indicates the point at which the estimated linear function crosses the y (per-capita demand)-axis. External Demands If the user chooses to specify demands externally, there are two external text files which must be created: An External Demand Data file, which includes monthly forecasted weather-normalized demand paths by node and by sector over the study period. A Daily Demand Weather Effects file, which includes daily adjustments for each day of the historical record to convert weather-normalized demands to observed demands. These files allow for a much richer and more nuanced description of future demands. The detailed format and syntax requirements for these files is available. The manner in which the simulation is to sample from the data in these files is described on the Demand Tab of the Study Definition Parameters form (see below). Defining the Simulation: The Study Definition Parameters Form The Study Definition Parameters form is accessed either from the tool bar or through the Edit menu. This form governs the manner in which the simulation will proceed. Study Control Tab: This tab includes the following study parameters: Study Start, Study End. The operating (water) years in which the study begins and ends. The month in which each operating year begins is defined on the Period Def tab (see below). # of Simulations. This governs the number of passes the model makes through the study period. This will vary depending on what questions are 17

18 being asked and the way that the user chooses to sample from the historical flow/weather years. Flow/Weather Sequence. This is where the user controls how the simulation samples from the historical distributions of streamflow and weather. Flow Method. There are three options for streamflow sampling: 1. Random. At the beginning of each year in each simulation, an historical streamflow year is randomly selected from the historical record. If this sampling option is selected, the user will also be given the option to check Use Constrained Record, which will cause the model to sample according to the years and weights specified in the Flow Record Sampling Subset data file (see below.) 2. Fixed. A fixed historical streamflow year is specified. This year s streamflow conditions are applied to all years of the study period. 3. Sequential. The first year of the first simulation is assigned the streamflow conditions for a user-specified historical year (1 st Seq Year). Ensuing years in that simulation are assigned consecutive historical streamflow conditions. If either the final year of the historical record or the limit set by the Seq Length variable is reached, the sequence returns to the 1 st Seq Year. Each simulation begins with a streamflow year that is one year later than the start of the previous simulation. For example, if we assume a multiple simulation study for which the simulation period runs from 2002 through 2020, the 1 st Seq Year is specified as 1940, and the Seq Length is set to 999 (unlimited): In the first simulation, year 2002 is assumed to have 1940 streamflow, year streamflow, etc. In the second simulation, year 2002 is assumed to have 1941 streamflow, year streamflow, etc. In the third simulation, year 2002 is assumed to have 1942 streamflow, year streamflow, etc. If we assume a single simulation for which the simulation period runs from 2002 through 2020, the 1 st Seq Year is specified as 1986, and the Seq Length is set to 7 years: 18

19 Year 2002 is assumed to have 1986 streamflow; year streamflow,... and year 2008 would have 1992 streamflow. Then in year 2009, the streamflow conditions would begin the 7-year sequence again with 1986 conditions. This 7-year sequence would repeat through the study period. Weather Meth. In most cases, the user would define the weather-year sampling method to be in lockstep with the streamflow year. Alternatively, it can be defined as either random or fixed, both assumed to be sampled independently of the streamflow year. This tab also includes three other check-boxes. Simulate Climate Change Effects. Checking this box indicates that the impacts of climate change on per-capita demand (see specification below) should be reflected in the simulation. Display Simulation Timing. Checking here ensures that the simulation timing will be displayed as the simulation proceeds. (On some systems, this may slightly slow the model run time.) Redispatch for Reliability. This adds a step to the simulation algorithm that refines the dispatch to improve the reliability of the system. Depending on the system configuration, this option can add to run times. For any system, experience will dictate whether the user wishes to select this option. Period Def Tab # Sim Days. The simulation is based on user-defined time steps. For each month, the user can define the number of simulation days (either 1 day or 28, 30 or 31 days) by double-clicking to toggle. One day indicates a monthly time step, in which case the simulation is based on average weather and total inflow values for the particular month. If 28, 30 or 31 days is chosen, the simulation for that calendar month is based on daily weather. (The Segment Pointer and # Dmd Segments variables refer to sub-daily time steps.) The In Peak Season variable indicates whether each month is considered part of the Peak Season for output reporting purposes. Operating Year Start Month, Flow Year Start Month. Here, the user specifies the start month for the simulation operating year, and the historical flow year, which governs the start of each year defined for flow and weather sampling. Thus, if a month 10 (October) flow year start date 19

20 is chosen, then flow year (or weather year) 1986 corresponds to October 1985 through September Other Params Tab This tab allows the user to specify a variety of other simulation parameters. Discount/Financial Reference: financial parameters: This section allows the user to define key Real Discount Rate to be used in all present worth calculations. Cost Reference Year. All costs are assumed to be expressed in this year s dollars. PV Time Zero, which is the year to which all present values will be calculated. Inflation Ptr. This vector of annual underlying inflation rates will be combined with the real escalation rates specified for each cost parameter to compute nominal dollar costs in any future year. Reliability Descriptors are parameters that define several of the reliability and supply/demand output charts. (Output charts are described below.) Random Seeds, which specifies the manner in which each of the stochastic variables will be randomly selected. Maintaining the same seeds from study to study will ensure that corresponding simulations in different studies will be based on the same flow, weather, demand, and local supply conditions. That will not be the case if Seed from clock is selected. (Note that these seeds will only apply if random sampling is chosen for the corresponding variable.) Resolution specifies the number of blocks into which unserved demand in each node is divided. As described above, each block is assigned an unserved demand cost. The number of blocks affects the distribution of unserved demand among nodes. Multiple blocks are also useful in controlling annual reservoir carryover. More blocks may also mean longer run times. Flow Adjustment Pointer points to a monthly distribution of multipliers by which all streamflows will be multiplied. This feature is useful to test the sensitivity of model results to lower (or higher) flows than experienced historically. (The Climate Change module described below provides the user with a much more finely-tuned approach to adjusting streamflows and demands due to future climate change. 20

21 Output Tab In addition to the output charts described below, the model is capable of producing a vast array of detailed text reports, which can be used to perform in depth diagnostics. This tab permits the user to determine which reports should be produced for what periods. Warning: Some of these reports are extremely large and may significantly affect the model s run time and system memory and storage constraints. If a combination of reports is selected that is likely to have these adverse affects, a message will appear at the beginning of a simulation warning the user of that fact. The Create Duration Curve Data for section allows the user to determine whether duration curves for different stochastic variables should be produced. The appropriate item must be checked for any curves of that type to be produced. For any checked item, duration curves will only be produced for those individual supplies or facilities (treatment plants, reservoirs, transmission links) for which such charts were selected (see above). Detailed descriptions of all of these reports are available. Text Data Files Tab As has been repeatedly alluded to, the model relies on several major text files of underlying data. The data in these files are not study-specific, and they are very seldom modified. These files do not reside in the individual study databases. Instead, data sets within these files are pointed to through the user interface. The paths and names of these files are specified in this tab. They include: Monthly Reservoir Evaporation in inches over the historical period of record. Monthly Reservoir Rain on Surface in inches over the period of record. Daily Temperature over the period of record. Daily Precipitation over the period of record. Daily Streamflows over the period of record. External Demand Data, which includes monthly forecasted weathernormalized demand paths by node over the study period. (Note: this file will only be used if the use of external demand data is specified (see below).) Daily Demand Weather Effects data, which includes daily adjustments for each day of the historical record to convert weather-normalized demands 21

22 to observed demands. (Note: this file will only be used if the use of external demand data is specified (see below).) Volume Limits by Flow/Study Year. This external volume limit file permits maximum annual source availability for single or multiple sources to vary as a function both of flow year and study year. Flow Record Sampling Subset. This file is used only if random sampling from a constrained record is chosen (see above). Detailed format and syntax instructions for these files are available. Note: The model automatically searches for these files in a \Data subdirectory in the default directory. If, for some reason, you install the files elsewhere, you will have to manually modify these paths. Clicking Reset Weather Files will reset the paths to the default. The files can be viewed and edited with any text editor. Double clicking on any of the file paths will open that file for viewing and editing in the text editor that the user has specified (see below). Demand Tab Most of the parameters on this tab are only used if the use external demand model box is checked. Otherwise, the (internal) demand forecast is defined on the edit pull-down menu (see above). External Demand Sampling Sampling Method. The user has three choices: Random will randomly select an external demand path at the beginning of each simulation. Stratified will select paths in intervals determined by the total number of paths and the number of simulations. For example, a 100-simulation study with a 300-path file will select every third path, beginning with path number 3. If the paths are ordered by growth rate, this option permits the user to ensure that the study will span the range of growth rates, while reducing the required number of simulations. Fixed path will maintain the designated path number for all simulations. Use Truncated Distribution. This option allows the user to specify the portion of the demand growth distribution from which to sample. This permits truncation of the tails to eliminate outliers. Alternatively, it allows the user to focus on either the high or low ends of the distribution. The 22

23 Other Tab Low Cutoff and High Cutoff parameters are expressed as cumulative probabilities. Use Weather-Effects Demand. Checking this box will tell the simulation to use the daily weather variations included in the Daily Demand Weather- Effects Data file. If unchecked, the model will ignore this file and use daily weather-normalized demands. Calibrate Daily to Monthly. Checking this box will ensure that daily weather-normalized demands are calibrated to the corresponding monthly totals. Smooth Days. This instructs the model to smooth demands using a running multi-day average prior to running the simulation. The smoothing period corresponds to the number of days entered in this field. External Volume Limit. This section defines the sampling method for the flow year of the external volume limits (see above). Normally, this flow year would be in lockstep with the current time step flow year, but the user is given the option to independently select the flow year to govern external volume limits. Disallow Simultaneous Reservoir Refill Purchase and Use for Demand. This box is checked to preclude reservoir fill and use of that reservoir to serve demand in the same time step. Defining the Remainder of the Study Edit Menu The remainder of the study database parameters are defined on the Edit pulldown menu. Some of the items on that menu have already been described. Study Definition. See discussion above. Transmission Line Data Schedule. See discussion above. Demand and Storage-Related Functions. This allows the nominal capacity of a transmission link to reflect hydraulic impacts of varying system demands in user-specified nodes or varying storage levels in userspecified reservoirs. The Demand Function Definition and Storage Function Definition tabs respectively allow definition of as many functions as possible. The functions linearly relate either demand or water in 23

24 storage to transmission capacity expressed as a percentage of nominal capacity. The Corridor Functions tab is where these functions are assigned to the appropriate transmission links. Local Supply. This menu item allows the user to define probabilistic local supplies that are not dispatched by the simulation and instead are treated as decrements to nodal demands. Reservoir. This is where key reservoir operating parameters are developed and edited. These parameters are pointed to in the Rule Curves, Evap, Streamflow tab of each of the reservoir data forms. Rule Curve Data. Each rule curve is expressed as end-of-month percentages of maximum useable storage volume. A shadow price is assigned to the zone above each curve. An escalation pointer is also specified for the shadow price. Volume/Surface Area Curves. These tables specify the relationship between volume and surface area. Intermediate values are linearly interpolated. These curves are used by the model to calculate evaporative losses and rain-on-surface additions. Coordinated Groups. The model permits transfers among the reservoirs within any of these user-defined groups, subject to transmission availability and rule-curve economics. Reservoir names must be put within single quotes ( ) with comma delimiters between names. The reservoir names must correspond precisely to the names in the system schematic. There is no limit to the number of groups or the number of reservoirs within a group. The check box allows a group to be enabled or disabled for a particular simulation. Instream Loss Data. These vectors define the average monthly percentage loss of spills to a downstream reservoir. They are referenced from each reservoir s data form (see above). Flow Augmentation Data. Each data set is a matrix which defines the release rate from a flow augmentation reservoir as a function of flow. (See discussion above of Flow Augmentation reservoirs.) Conservation Programs. An unlimited number of conservation programs can be defined in terms of their participation rates, savings, and costs. Program editing can be done in one of two views, an all programs and an individual programs view. Programs are most easily created in the individual programs view, which is described as follows: 24

25 Individual Programs View Program Parameters Tab The left-hand column includes the savings parameters associated with the program. Use annual savings. This checkbox allows users to select a method of defining per-participant savings. If the box is checked, total annual savings are specified, along with a pointer to a monthly distribution, which defines how those savings are distributed across the year. If the box is unchecked, daily summer (peak-season) and daily winter (off-peak season) savings are specified. Unit summer savings. If the annual savings checkbox is not selected, the daily per-participant savings in gallons during the peak-season are entered here. Unit winter savings. If the annual savings checkbox is not selected, the daily per-participant savings in gallons during the off-peakseason are entered here. Unit annual savings. If the annual savings checkbox is selected, the annual per-participant savings in gallons are entered here. Monthly distribution. If the annual savings checkbox is selected, a monthly pointer is identified that allocated the savings across the months of the year. Savings life. The number of years that savings persist, measured from the initial participation date. Nat turnover rate. The annual percentage natural turnover, if any, of fixtures due, for example, to plumbing codes. The annual savings associated with the program will be reduced due to this assumed natural turnover. This input must be entered as a decimal. Thus,.04 is entered for 4%. Savings Node Alloc. A pointer to a demand node distribution for this program s savings. Daily Sav Shape. desired. Controls the sub-daily pattern of savings, if Program Group. If desired, an identifier of the conservation program group to which this program belongs. These groupings are 25

26 used in various output charts. See below for defining conservation program group names. The right-hand column includes the program s cost parameters: Initial Var Admin. The incremental cost, other than participant incentives, incurred by the utility per participant at the time that the participant enters the program. Examples include the cost of an audit or an installation. Util Incentive: The incentive provided by the utility to each participant taking action at the time of program entry. Periodic Var Admin. The incremental cost, if any, incurred by the utility per participant at specified intervals to maintain savings over the savings life. An example would be follow-up contacts with customers who have been audited. Interval. The interval, in years, at which the utility incurs the periodic variable administrative cost during the savings life. Fixed Admin. The cost incurred by the utility per year as long as there are new program participants. Customer Cost. The cost borne by each participant taking action at the time of program entry. This cost is net of any incentive provided by the utility. Utility Financing. A pointer which specifies the manner in which the utility incentive will be financed. Cust Financing. A pointer which specifies the manner in which the customer cost will be financed. Capital Real Escl. A pointer to the annual real escalation rates for the utility incentive and customer costs. Admin Real Escl. A pointer to the annual real escalation rates for all other conservation costs. Cost Node Alloc. If desired, a pointer which specifies how the costs of this program will be allocated to demand nodes. 26

27 Schedule Tab This tab specifies the manner in which this program will be scheduled over time. Start Year. implementation. This is the year that the program begins Year of Schedule. The Start Year is year 1. New Participants. each year. The number of new program participants for Partic Taking Action. For programs (e.g. audits) in which participating customers may or may not take action (e.g. upgrade an irrigation system), this is the percentage of the New Participants taking action. Incentives are assumed to be paid only to these customers. Non-freeriders. Freeriders are participants who would have taken the action even without utility intervention. Programmatic savings (see below) are assumed to be achieved by these customers. This entry is the percentage of New Participants who are not freeriders. Other Admin. These are costs that occur in particular years, not otherwise accounted for. All Programs View This matrix includes all of the program data discussed above. Data can also be edited on this form. Right clicking on the name of any program will permit the user to view and edit the program schedule for that program. This form also provides a convenient way to enable or disable some or all programs simply by checking the boxes in the column headed Enabled. The form also includes buttons to enable or disable all programs. Program Group Definition. This is where the names of conservation program groupings (see above) are defined. Water Rights. There are two types of water rights, Flow-Based and Demand- Based. In addition, this is where the flow-dependent Instream Rights discussed above for river diversions are defined. 27

28 Flow-Based Rights These are by far the most common type of water right. Each set of flowbased rights is specified as a hierarchy of rights. The hierarchy currently includes three types of water rights: senior, instream, and junior. Each right is a series of 12 monthly maximum rates of diversion. As the names imply, the senior rights are senior to the instream rights; the junior rights are junior to the instream rights. As discussed above, these water rights may be shared by multiple projects. Demand-Based Rights In this case, the right to divert is a function of demand in one or more specified nodes. Current logic has the right to unlimited diversion (subject to actual streamflow) up to the earlier of either a fixed date (e.g. June 15) or the first time the multi-day average demand in the designated node(s) exceeds a designated level. After that event, diversions are prohibited until a second fixed date (e.g. November 1). User inputs include: Demand node(s) which govern diversion rights. Schedule of demand triggers to terminate diversions. As is the case with all annual schedules in Confluence, it is not necessary to specify values for all years of the planning period. The model logic will linearly interpolate between non-consecutive years, and will assume that the value before the first year entered or after the final year entered are equal the initial or final entry respectively. Number of days over which multi-day average demand is to be calculated. The fixed cutoff date. The fixed turn-on date. Monthly Distributions. Each row in this table defines a monthly distribution pointer, which are invoked from many places in the user interface. Where appropriate, the simulation logic normalizes the sum of the monthly entries to one. Growth/Escalation Rates. Each set defined here defines a vector of annual growth rates, which can be invoked from many places in the user interface. Cumulative growth rates are compounded from these annual percentage rates. As indicated above, growth rates for those intermediate years which are not 28

29 shown in the schedule are estimated using linear interpolation. The growth rate for years prior to the first specified year is assumed to be equal to the first rate specified; similarly, growth rates for years following the last year specified are assumed to remain equal to the last rate specified. New pointers are created by clicking on New. Node Allocation Data. Each set defined here defines a matrix of node allocation percentages for future years, which are invoked from many places in the user interface. For any year, the model will normalize the sum of the entries to 100%. For intermediate years, allocation percentages for each node are estimated through linear interpolation. Finance Data. Each set defined here specifies the manner in which capital investments will be financed. Each set consists of a financing (amortization) period and a real interest rate. These are invoked at each place in the interface where a capital expenditure is defined. Cash Flow Data. Each set defined here specifies the annual cash flow associated with capital expenditures. These sets are defined by one or more annual percentages, the sum of which is normalized to 100%, which define the cash flow up to and including the year preceding the on-line date of a facility. Joint Hydraulic Functions. Each set defined here specifies the supply project and the functional form which limits the maximum delivery capacity of any other supply project which points to this function. These functions are intended to capture significant joint hydraulic limitations. Turbidity Constraints. Each set defined here specifies daily rainfall conditions under which a diversion supply will be shut down. There are two types of functions: Type 1: Source is shut down on the current day plus P2 additional days if current day rainfall exceeds P1 inches. Type 2: Source is shut down on current day plus the truncated integer value of (P2 * current day rainfall) additional days if current day rainfall exceeds P1 inches. Step Capacity Functions. Each set defined here specifies fractions of a supply project s maximum capacity as the only levels at which the project can operate because, for example, of discrete pump capacities. Up to 10 operating levels can be specified in any single function. Each is expressed as a decimal value, which the simulation logic multiplies by the project s nominal capacity. 29

30 Joint Project Volume Limits. Here, the user can set production limits which apply to sets of supply projects. The user can define as many sets as desired. For each set, the included projects are specified. The user then defines an annual schedule of joint production limits, the initial month of the annual volume computation, and the initial production level that should be assumed at the beginning of the study period (if the study start month does not coincide with the annual computation period). The user also has the option to define volume limits as a function of both flow year and operating year in an external text file by checking the Use External Limit box. The user must specify the name of the data set in that external file. The user can also define Monthly Constraints corresponding to different production ranges. Node Output Groups. Here, the user can define groups into which demand nodes will be divided in output charts. The default is for each demand node to be shown individually. Modify Database Units. The user can specify the units in which key input parameters are to be expressed. The model will then automatically convert all relevant parameters to the new units. Specifying Climate Change Impacts Confluence has been upgraded to enable users to readily specify the impacts of climate change scenarios on both water supply and demand: Supply Confluence users can define sets of monthly factors as multipliers of the historical streamflows contained in the external flow file (see above). Through a simple grid structure, these flow adjustment factors can be varied by: Hydrologic Year, to reflect potential differences in how flows would change under different hydrologic (e.g. wet, average, and dry) conditions. Source, to reflect potential differences in how the flows for different watersheds and/or diversion points may be affected differently by a climate change scenario. Time, to recognize that climate change impacts are expected to grow in the future, the flow adjustments can likewise change over time. 30

31 Demand Climate change can affect water demands in two ways. Per-customer demands may change due to modified temperature and rainfall patterns. In addition, population growth forecasts can be affected by altered migration patterns. The per-customer demand impact is specified in the same grid structure as above by increasing or decreasing the historical temperature and precipitation if demand is specified internally, or by directly adjusting historical demands for different weather years if demand is specified externally. Altered patterns of migration into and out of the region are handled by applying a set of annual adjustment factors to baseline population growth (See above discussion of Climate Change Growth Effects in Demand Data form.) There are two Climate Change grids which can be accessed through the Edit menu or by clicking on the sun symbol in the toolbar. Following are discussions of these grids. Climate Change Category Def Grid Figure 1 shows a portion of the Streamflow and Internal Demand portions of a sample Category Definition grid, which is the first step in defining climate change impacts. Figure 1 Climate Change Category Definition Grid The entries in each cell of the grid point to series of monthly distributions. Thus, in a 1970 weather year, with demand defined internally, daily temperature would be changed according to the monthly adders contained in the series Temp_Norm. In a 1972 weather year, the change in temperature would be governed by the series Temp_Cool, and in 1973 by Temp_Hot. 31

32 The principle is similar for Streamflow and External Demand, with the following modifications: Streamflow. Each streamflow set can have its own series to reflect different climate change impacts on different streams or watersheds. For flow sets for which there is no series, the Default series will apply. External Demand. Rather than series for precipitation and temperature, there are series for individual demand nodes, and a Default series which applies to demand nodes for which an individual series is not specified. The second grid (see Figure 2) defines each of these series. Thus, beginning in 2015, the series Temp_Norm (which Figure 1 tells us applies for weather years 1970 and 1971) adds to historical daily temperature the number of degrees (F) contained in the monthly distribution T_1. In 2020, the adders change to T_2, and in 2025 to T_3. In contrast, for the series Temp_Cool (which applies to weather years 1972 and 1975), the adjustments don t begin until 2020, when the adders specified in T_1 apply. Figure 2 Climate Change Annual Definition Grid Each of these monthly distributions is then defined as a row in the Monthly Distributions matrix discussed above. Figure 3 shows a portion of that matrix. 32

33 Figure 3 Monthly Distributions of Climate Change Impacts The simulation interprets the entries that apply to temperature as adding to base daily temperature, and those that apply to streamflows, precipitation, and external demand as multiplying the appropriate base quantities. Thus, in those weather years for which Temp_Norm applies (e.g. 1970), the daily base temperature in May-October will be increased by 1 o F between 2015 and 2019, by 1.5 o F between 2020 and 2024, and by 2 o F beginning in For Hudson Creek, in those flow years for which SF_Low applies (e.g. 1972), the daily base flows will be multiplied by the factors contained in SF_1 from ; SF_2 from ; SF_3 from ; and SF_4 beginning in This three-step process provides maximum flexibility to vary climate change impacts over time and space, and thereby specify and compare climate change scenarios of any degree of complexity. Depending on available data and analytic resources, as much or as little of this flexibility as desired can be utilized. View Menu Most of the items on the View menu can also be accessed directly from the toolbar. They include: Map. This opens the system schematic. The globe icon on the toolbar performs the same function. 33