diff --git a/in/parameters.json b/in/parameters.json
index 9515ad5..8206839 100644
--- a/in/parameters.json
+++ b/in/parameters.json
@@ -93,5 +93,11 @@
         "precid": 1,
         "climid": 1,
         "windid": [1, 1, 1, 1]
-    }
+    },
+    "timeseries_to_catflow_precip": {
+        "raindat": "./in/raindat.csv",
+        "start.time": "01.01.2004 00:00:00",
+        "time.unit": "h",
+        "faktor.p": 1
+    } 
 }
\ No newline at end of file
diff --git a/src/lib.R b/src/lib.R
index e2acbcc..627b2ff 100644
--- a/src/lib.R
+++ b/src/lib.R
@@ -1,8 +1,13 @@
 # source catlib.R
 source("catlib.R")
 
-# implement "workflow scripts"
+
 lib_preprocess_catflow <- function(params) {
+    ###
+    # CATFLOW preprocessing workflow, creates all the files
+    # necessary to start a CATFLOW run.
+    ###
+
     # (1) make geometry from .tif files
     catlib_make_geometry_representative_hillslope(params)
 
@@ -33,3 +38,31 @@ lib_preprocess_catflow <- function(params) {
     # (8) complete the CATFLOW file structure
     catlib_complete_file_structure(params)
 }
+
+
+lib_timeseries_to_catflow_precip <- function(data, start.time, time.unit, faktor.p) {
+    ###
+    # Convert precipitation time series data into the
+    # format required by CATFLOW.
+    #
+    # Always give the precipitation data (data) in mm/h.
+    ###
+
+    # Convert the time column to a datetime object
+    data[, 1] <- as.POSIXct(data$time, format = "%Y-%m-%d %H:%M:%S")
+
+    if (start.time) {
+        # Create a new column with the hours since the given start.time
+        data$hours <- as.numeric(difftime(data[, 1], start.time, units = "hours"))
+    } else {
+        # Create a new column with the hours since the start of the time series
+        data$hours <- as.numeric(difftime(data[, 1], min(data$time), units = "hours"))
+    }
+
+    catlib_write_precip(
+        raindat = data,
+        start.time = start.time,
+        time.unit = time.unit,
+        faktor.p = faktor.p
+    )
+}
diff --git a/src/run.R b/src/run.R
index bb53a76..22d1d89 100644
--- a/src/run.R
+++ b/src/run.R
@@ -51,6 +51,14 @@ if (toolname == "make_geometry") {
 } else if (toolname == "preprocess_catflow") {
     lib_preprocess_catflow(params)
 
+} else if (toolname == "timeseries_to_catflow_precip") {
+    lib_timeseries_to_catflow_precip(
+        data = params$data,
+        start.time = params$start.time,
+        time.unit = params$time.unit,
+        faktor.p = params$faktor.p
+        )
+        
 } else {
     # in any other case, the tool was invalid or not configured
     print(paste("[", Sys.time(), "] Either no TOOL_RUN environment variable available, or '", toolname, "' is not valid.\n", sep = ""))
diff --git a/src/tool.yml b/src/tool.yml
index 954b825..682fa26 100644
--- a/src/tool.yml
+++ b/src/tool.yml
@@ -604,4 +604,33 @@ tools:
           Wind direction ID: either a vector of numbers representing different 
           wind direction sectors which are to be assigned to all surface nodes, 
           or a matrix of numbers with the same number of rows as xsi and as 
-          many columns as there are wind direction sectors (default: 4 sectors)
+          many columns as there are wind direction sectors (default: 4 sectors).
+  timeseries_to_catflow_precip:
+    title: Convert precipitation timeseries to CATFLOW specific format
+    description: |
+      CATFLOW requires a precipitation record from which the rainfall intensities 
+      are interpolated between discrete time steps; rainfall intensities are thus 
+      only needed at those time steps when they are changing.
+      This tool converts a precipitation timeseries to CATFLOW specific format.
+    version: 0.1
+    parameters:
+      data:
+        type: file
+        description: |
+          Rainfall data: data frame with two columns; first column must be 
+          timestamps ("%Y-%m-%d %H:%M:%S"), the second column contains the
+          precipitation data.
+      start.time: 
+        type: string
+        description: Start date for the simulation ("%Y-%m-%d %H:%M:%S")
+        optional: true
+      time.unit: 
+        type: string
+        description: Time units of the precipitation record
+        default: "h"
+      faktor.p:
+        type: float
+        description: |
+          Conversion factor for rain rate to m/s (only needed if rate is NOT 
+          given as mm per 'time.unit')
+        optional: true