TMDL Modeling Toolbox Loading Simulation Program in C

TMDL Modeling Toolbox Loading Simulation Program in C++ (LSPC) John Riverson Tetra Tech Inc.

TMDL Modeling Toolbox – LSPC Presentation Outline • LSPC Design Considerations • LSPC GIS Control Center • LSPC Model

TMDL Modeling Toolbox – LSPC Overview • LSPC = Loading Simulation Program, C++ • Streamlined Hydrologic Simulation Program Fortran (HSPF) algorithms for pervious and impervious land flow and pollutant transport, coded with Visual C++ in an object-oriented environment • Visual C++ programming architecture allows for seamless integration with modern-day, widely available software such as Microsoft Access, and Excel • Key watershed modeling component of the TMDL Toolbox (developed and maintained by EPA Region 4 with support from Tetra Tech) • TMDLs successfully developed in AL, MS, SC, GA, CA, KY, TN, WV, VA, MD, AZ, OH, Puerto Rico, and U. S. V. I.

TMDL Modeling Toolbox – LSPC Key Design Considerations • Potential for very large-scale modeling (e. g. HUC -wide or Statewide) • Increase efficiency of model setup and execution (eliminate unnecessary, repetitive user input, hence minimizes the chance of human error) • Simplify model output • Tailored for TMDL development – Handles potential nonpoint and point sources – Calculation tools – Archival system

TMDL Modeling Toolbox – LSPC Key Design Considerations, cont. • Highly adaptable design and programming architecture that allows for future modular additions and/or improvements • Simplify model sharing and distribution The LSPC Map Objects GIS interface, which is compatible with Arc. View shapefiles, acts as the control center for launching watershed model scenarios. The stand-alone interface communicates with shapefiles and the Access database. Therefore, once a watershed system is created, it is easily transferable to users who may not have Arc. View or MS Access

TMDL Modeling Toolbox – LSPC Components • • Stand-alone GIS control center Data management tools Data inventory tools Data analysis tools Dynamic watershed model TMDL calculation Model results analysis

TMDL Modeling Toolbox – LSPC Component Interactions LSPC Model MS Access Database LSPC Weather text file

TMDL Modeling Toolbox – LSPC Data Flow Schematic Spatial Inventory Environmental data • Weather data • Water quality monitoring data • USGS gage data • Soil distribution Model Results • Simulation Results • Loading distribution (land use) • Loads discharge into reach • Violation distribution Watershed Model and TMDL Tool Watershed data • Land use area • Reach geometry • Point source monitoring data • Permit limits Data Analysis Tool Interactive GIS Control Center • Watershed delineation • Reaches • 303(d) list • Location of point sources • Location of water quality stations • Location of gage stations Database Data Management GIS Layers

TMDL Modeling Toolbox – LSPC Exploring LSPC Functionality GIS Control Center Watershed Model

TMDL Modeling Toolbox – LSPC GIS Control Center

TMDL Modeling Toolbox – LSPC GIS Interface • Once a project is created, LSPC can view GIS layers (shape files) and operate independent of Arc. View or Spatial Analyst • GIS Interface supports some basic GIS functions – – – Zoom in/out, Pan Identify tool Shape selection Add/remove/move points in point themes Edit associated attribute data

TMDL Modeling Toolbox – LSPC GIS Layer Definition These defined layers are used in the system for data linkage • • Watershed Reach Discharge General Gage Listed water Water quality

TMDL Modeling Toolbox – LSPC Data management & Data Inventory • Data management allows users to edit Access database tables from LSPC • Data inventory tool allows user to launch queries, built data reports, and analyze model results

TMDL Modeling Toolbox – LSPC Data Management • User is provided a window to select a table in the database to lookup • LSPC calls MS Access database file in the background MS Access Database

TMDL Modeling Toolbox – LSPC Data Management • Accesible Tables Include: – – – – Point Sources Simulation Time File Paths Landuse Model Mapping Weather Stations WQ Parameters WQ Data MS Access Database

TMDL Modeling Toolbox – LSPC Data Inventory • Some of the predefined queries are: – Watershed/sub-watershed characteristics – Land use summary – Statistics for water quality and flow data – Modeled results summaries

TMDL Modeling Toolbox – LSPC MS Access Database Data Inventory 1. Select Category 2. Select Query (Shift for multiple) 3. View Summary Table

TMDL Modeling Toolbox – LSPC Data Analysis • • View water quality data View USGS flow data View input weather data View Model Results Statistics of any time series Correlation analysis Violation Analysis

TMDL Modeling Toolbox – LSPC Data Analysis - Available datasets - Flow data - WQ data - Model output - Avalable timeseries within selected dataset

TMDL Modeling Toolbox – LSPC Watershed Model

TMDL Modeling Toolbox – LSPC Modules from HSPF RCHRES Modules PQUAL and IQUAL Modules HYDR ADCALC Hydraulic behavior , pollutant transport CONS Conservative constituents HTRCH Heat exchange, water temperature SEDTRN Behavior of inorganic sediment GQUAL Generalized quality constituent PWATER Water budget for pervious land IWATER Water budget for impervious land SNOW Incorporates snow fall & melt into water budget SEDMNT Production and removal of sediment PWTGAS Est. water temperature, dissolved gas concentrations IQUAL Simple relationships w/ solids and water yield PQUAL Simple relationships w/ sediment and water yield

TMDL Modeling Toolbox – LSPC Data Representation in LSPC Each Landuse (Physical): • Average Slope • Average length of overland flow Each Subwatershed: • Landuse Distribution • Weather Data • Representative Soil Type Each Landuse (Process): • Hydrology • Sediment yield • Pollutant load generation

TMDL Modeling Toolbox – LSPC Subwatershed Delineation • Subdivision of the watershed intro discrete components • Delineation based on: – elevation (topographic data) – stream connectivity – location of flow and water quality monitoring stations • Each subwatershed is modeled with 1 representative stream • Each subwatershed is modeled with 1 representative meteorological time series

TMDL Modeling Toolbox – LSPC Top-down Modeling Approach Project 1 (upstream) • User may choose to run the model in sections to optimize calibration time. Calibration Point Project 2 (downstream)

TMDL Modeling Toolbox – LSPC Land Simulation • Each subwatershed is represented by multiple land units (based on landuse coverages) • Land units are either pervious or impervious • Model algorithms are run for each individual land unit

TMDL Modeling Toolbox – LSPC Model Parameter Mapping • Designed to facilitate the development of regional comprehensive default parameter databases • Automatic parameter mapping is based on systematically similar physical attributes (i. e. soil hydrology characteristics) • Model Parameter Options – Save calibrated model parameters – Add new parameter set to the database

TMDL Modeling Toolbox – LSPC Model Parameter Mapping Default Parameter Watershed Group 1 Watershed 1 (A) Soil type A Watershed 2 (A) Soil type B Watershed 3 (C) Group 2 Watershed 4 (D) Soil type C ro G Watershed 5 (A) up 3 Soil type D Watershed 6 (B) Watershed 7 (C) Group 4 Soil type A(1) Soil type B(2) Soil type C(3) Watershed 8 (C) Soil type D(4)

TMDL Modeling Toolbox – LSPC GIS analysis is used to determine subbasin physical attributes and select associated initial model parameters Mapping modeling parameters Model parameter database Update parameters Model interface loads parameters User may edit parameters Run Model Update default parameters Add new default set Add new Parameter set

TMDL Modeling Toolbox – LSPC Weather Data Application Precipitation Pot. ET Air Temperature Wind Speed Solar Radiation Dewpoint Temp. Cloud Cover Reaches Quality Heat Required Water Sediment Water Snow Temp Land Optional

TMDL Modeling Toolbox – LSPC Hydrology • Hydrologic Components: – – – – Precipitation Interception Evapotranspiration Overland flow Infiltration Interflow Subsurface storage – Groundwater flow – Groundwater loss Source: Stanford Watershed Model

TMDL Modeling Toolbox – LSPC Baseflow Interflow Runoff Components of Hydrograph Surface runoff overland flow Interflow - flow through surficial layers of soil Baseflow - groundwater seepage from springs and aquifers directly to the stream channel

TMDL Modeling Toolbox – LSPC Snowmelt Schematic Precipitation Snow or Rain Evaporation from Snow Pack Total Snow Pack Atmospheric Conditions S now Liquid Ice Ground

TMDL Modeling Toolbox – LSPC Stream Hydraulics • Completely mixed reach (single layer) • Unidirectional flow • Flow routing by kinematic wave or storagerouting method (i. e. conservation of momentum not considered) • Requires function table (F-Table) for depthvolume-discharge relationship for each reach. • Calculates outflow, depth, volume, surface area, and selected auxiliary variables (velocity, crosssectional area, bed shear velocity/stress)

TMDL Modeling Toolbox – LSPC Function Table • Area (surface) = Top width * length • Volume = Cross sectional area * length m 21 1 • Outflow can be withdrawal, m 11 1 spillway discharge Q 2 = A 2 V 2 or outflow at the downstream end of Area Depth a reach 0. 0 • Stream Flow = 0. 08 10. 81 Cross sectional 0. 80 11. 36 1. 20 11. 68 area * velocity Q 1 = A 1 V 1 m 21 1 Volume 0. 0 Outflow 0. 0 0. 86 2. 12 8. 84 13. 45 98. 09 192. 51

TMDL Modeling Toolbox – LSPC F-Table / Cross-Section Tool Draw/Refine Stream Cross-sections LSPC computes associated F-Table

TMDL Modeling Toolbox – LSPC Erosion and Sediment Processes • Pervious land areas – Erosion is a function of land use activity, soil characteristics, slope, land cover, and precipitation – Erosion occurs due to rainfall “energy” • Detachment of soil particles • Washoff of detached material Raindrop impact detaches soil particles

TMDL Modeling Toolbox – LSPC Sediment Processes Common to both pervious and impervious land Net vertical sediment input Lateral input of sediment to surface Detached sediment storage Sediment attachment Transport offsite of detached sediment Total removal of soil and sediment Detachment of soil by rainfall Soil Matrix Scour of soil matrix

TMDL Modeling Toolbox – LSPC Sediment Budget and Transport • Land Processes – Production and removal of sediment from land • Washoff of loose sediment • Scouring of soil matrix • Stream Channel Processes – Transport, deposition and scour of sediment in the stream channels

TMDL Modeling Toolbox – LSPC Overland Water Quality Processes • Urban Land Units – Impervious areas • Dust and dirt build-up functions – Pervious areas • Dissolved pollutants with runoff • Erosion and adsorbed pollutants with sediment • Rural Land Units – Erosion and adsorbed pollutants with sediment – Dissolved pollutants with runoff

TMDL Modeling Toolbox – LSPC Overland General Quality (Rainfall-driven processes) Constituent Build-up • Accumulation at a constant rate for a constituent • Computed at daily time interval 2 Build up Washoff Limit Storage 1 1 2 1 Time Change of storage with time

TMDL Modeling Toolbox – LSPC In-stream Simulation of Generalized Quality Constituent • Simulates dissolved and sediment associated general quality constituents • Processes applicable to dissolved general quality constituents include: – Advection of dissolved material (dominant process in the watershed) – Decay processes (1 st order decay used to represent net nutrient losses attributed to settling, transformations, etc. )

TMDL Modeling Toolbox – LSPC Model Results Analysis • General data analysis tool – – Analyze timeseries flows and concentrations Evaluate average annual loads by landuse/subbasin Generate unit load calculations and summaries Generate loading and allocation tables • Customized data analysis – Uses standard MS Access queries – Results are easily pasted into Excel for analysis not provided within the system itself

TMDL Modeling Toolbox – LSPC Model Results • Model results saved in the following tables: – Annual loads of each land use for every subwatershed (Baseline and TMDL) – Annual loads transported to the stream (Baseline and TMDL) – Pollutant adjustment scenarios by land use and by watershed

TMDL Modeling Toolbox – LSPC Hydrology Calibration • Analytical Considerations Level of Effort – Annual water balance – Seasonal / monthly distribution – Distribution of hydrograph components • Storm flow • Base flow – Snowfall / snowmelt influence

TMDL Modeling Toolbox – LSPC Hydrology Calibration Methods • • Hourly/Daily/Monthly Timeseries Monthly Scatter/Balance Plots Seasonal Plots (Multi-Year Composites) Flow Duration Curves Flow Accumulation Curves Cumulative Error Statistics Hydrograph Components

TMDL Modeling Toolbox – LSPC

TMDL Modeling Toolbox – LSPC TMDL Calculation • Support TMDL study and loads allocation • Provides functions to evaluate TMDLs – – Level 1: General upstream load control Level 2: General upstream land use control Level 3: Point source control Level 4: Land use and pollutant control by subbasin