StoDyM

For a given check dam system (dams' location and storage capacity) in the stream path of a catchment, StoDyM adopts an annual time step and calculates as output the annual changes in the dams' storage capacity (due to sediment trapping), the annual values of the Sediment Delivery Ratio (SDR, ratio between the sediment discharged at the catchment's outlet and delivered to the stream path), and the life expectancy of each check dam.

Inputs:

• (c_pn, pa_v): First component is the pixel number (excluding "NoData" pixel) of the catchment's DEM raster and the second component is the area of a single pixel in km².
• ste_tv: Threshold value of Sediment Trapping Efficiency (STE). It is given as 10% by threshold value.
• (dle_min, dle_max): First and second components of the dams' minimum and maximum life expectancy in years, respectively.
• (csw_kg, s_sg): Fist component is the conversion of sediment mass unit to Kg and the second one is the sediment specific gravity in Kg/m³. For the present example, sediment mass is converted from Ton to Kg as 907.185, and the sediment specific gravity 2.65 is converted to 2650 Kg/m³
• sc_fn: File name of stream characteristics data (e.g., Shejiagou_Stream_Characteristics.xlsx), which contains the required information of each stream segment with the columns (please see the "GIS_Data" folder of flow accumulation ("S_FA.tif"), stream link ("S_SL.tif"), and potential dams' location ("S_pdl.shp") for better understanding)
  • SID: Identification number of the stream segment
  • NSID: Identification number of the next connected downstream segment
  • DFA: Flow accumulation value at the potential dam location (extracted from the flow accumulation raster)
  • SSI: Sediment input to the stream segment (calculated by WaTEM/SEDEM)
• dtl_a: Array of dams' targeted location in terms of selected stream segments' identification number (please supply the value in ascending order and don't repeat any value since a segment cannot contain more than one dam)
• dsc_a: Array of dams' storage capacity according to the given order of dams' targeted location

Output:

The output is an ordered dictionary with the keys:

• "Dam_Characteristics": Each row gives the dam's ID (DID), SID, initial storage capacity in m³ (ISC), drainage area as a percentage of the total catchment area (IDA), and life expectancy in years (LE)
• "Storage_Variation": The normalized storage variation (i.e., the ratio between the available and initial storage capacity) of each dam with annual time step
• "SDR_Variation": The variation of SDR with annual time step
• "Summary": A short summary of check dam system's inital total storage capacity (ITSC), initial total drainage area (ITDA), average life expectancy in years (LE_A), and four objective values of multi-objective evoutionary algorithm in terms of average life expectancy (O-LE), storgae dynamics (O-SD), short-term SDR (O-SDR,ST), and long-term SDR (O-SDR,LT)

By default, the output of StoDyM cannot be saved in excel file. To save the data, please supply "excel_file=True" in the function "stodym_output_write(excel_file=False, stodym_fp="StoDyM_Output.xlsx")". The data will be saved in the current folder with default file name "StoDyM_Output.xlsx". If the data needs to be saved in other folder, please supply "stodym_fp="C\Users\My_Data.xlsx".

StoDyM_MOEA

For a given number of check dams in a catchment, this numerical framework optimizes the dams' location and storage capacity in the catchment's stream path. Please take a look on the StoDyM inputs before read the following inputs required for the Multi-Objective Evolutionary Algorithm (MOEA).

Requirement

Python module Platypus for evolutionary computing (https://github.com/Project-Platypus/Platypus)

Inputs

• cpn_d: Dictionary of catchments' pixel number
• cdn_d: Dictionary of catchments' dam number
• cdscul_d: Dictionary of upper limit of dams' initial total storage capacity
• Storage capaicty of dams: It can be provided by either Integer (dscdv_i = True) or Subset (dscdv_i = False) class from Platypus
  • cdsci_d: Dictionary of dams' storage capacity in terms of Integer class. The user needs to provide a multiplier of Integer (dsc_mult, default value is 1000) to get the actual dams' storage capacity. It can be adjusted according to the range of Integer and storage capacity. Here, the user cannot set a specific search space of dams' storage capacity.
  • cdscs_d: Dictionary of dams' storage capacity in terms of Subset class. Here, the user can set a specific search space of dams' storage capacity by providing a list (default is list(range(start, end, step))).
• eps_v: Value of epsilon required for EpsNSGAII (default is 0.001)
• cn_s: Name of catchment
• (o_no, ps_no, fe_no, s_no, cc_no): Numbers of objectives (o_no), population size (ps_no), function evaluations (fe_no), seed (s_no), and computer core (cc_no)
• od_l: objective decision list of maximization and minimization in case user change any objective
• cs_l: constraint list in case user change any constraint
• u_p: array of Utopian point (1 for maximization and 0 for minimization)

Note that each dictionary contains two keys "Shejiagou" and "Majiagou", since the framework is tested on these two catchments. The user can insert arbitraty number of catchments.

Outputs

For each combination of algorithm and problem, the numerical framework computes the Pareto-front set from the merged solutions of all seeds and saves the Pareto-front set (sheet_name="Pareto_Front") and simultion time (sheet_name="Time") in excel file. Each row of the "Pareto_Front" sheet represents a Pareo-front solution with the information of

• dams' location (DO, D1 etc.)
• dams' storage capacity (SCO, SC1 etc. in m³)
• intial total storage capacity (ITSC, in m³)
• intial total drainage area as a percentage of the catchment area (ITDA)
• four objective values of average life expectancy (O-LE), storgae dynamics (O-SD), short-term SDR (O-SDR,ST), and long-term SDR (O-SDR,LT)
• Life expectancy of each dam (LE0, LE1 etc. in years)
• Average life expectancy (LE_A) in years
• Distance from Utopian point (last column)

Note that SCN and LEN represent the features of DN dam, where N = 0, 1, 2, ..., n and n is the number of dams