# Hydrology Simulator Kupa and Korana - Introduction

## Before we start

This simulator is more complex than the other ones, because it is not only a meteorological simulator but also involves a hydrological component. Here you can see how the weather predictions and situations affect other services and why there is a need for close collaboration. In an ideal situation, you as a meteorologist would be paired up with a hydrologist, but since there might be no such possibility, you will get some basic information on hydrological data in the introduction.

## Weather situation before October 15th

A few days before today's exercise, there was a rainy episode caused by a cyclone (figure 1). You can take a look at the amount of precipitation in the images below.

Figure 1: Surface analysis of synoptic situation on October 10th. There is a well defined cyclone above Italy with a warm front over Croatia.

Use the mouse cursor to slide through images.

Figure 2, a)-d): 24h precipitation amounts during the last four days (11 October - 14 October)

## Hydrological data - Product explanation

### 1. South East Europe Flash Flood GuidanceSystem (SEEFFGS)

#### Current situation:

#### Merged Mean Areal Precipitation

Catchment accumulated rainfall in the last 6 hours. It is based on satellite data (Microwave-adjusted Global Hydroestimator and Global Hydroestimator) and the data from meteorological stations.

Take a look at the data for the previous day. There is a legend on the right side of the image. If there was no rain the catchment will be white.

Use the mouse cursor to slide through images.

Figure 3 a)-d): Catchment accumulated rainfall in the last 6 hours on October 14th

#### Average Soil Moisture

Average Soil Moisture is a result of the Sacramento model. It shows soil moisture in the last 6 hours before the time of the image. To get familiar with the product, please take a look at the data provided for the day before. There is a legend on the right side of each image showing saturation of a catchment. Gray means dry, while the darkest blues shows almost completely or completely saturated catchment.

Use the mouse cursor to slide through images.

Figure 4, a)-d): Average soil moisture for catchments on October 14th

#### Forecasts:

#### Forecast Mean Areal Precipitation

Forecast of the mean areal precipitation for each catchment is based on Aladin model. It provides forecast 6 hours in advance. The same legend is used as for Merged Mean areal precipitation (figure 3).

### EFAS (European Flood Awareness System) forecast

Flash flood forecast for the next 120h. Big purple triangle shows the probability of exceeding a 20 year return period magnitude of the surface runoff index, for the forecasted start of the event is in < 72 hours. It is calculated every 12 hours.

Figure 5: Flash flood forecast on October 14th for 00 UTC and 12 UTC

Different river tributaries are colored according to the return period:

- Red - a return period >5 and <20 years. Significant flooding is expected.
- Yellow - a return period >2 and <5 years. Bankfull conditions or slightly higher expected. If flooding occurs no significant damages are expected.
- Blue - a return period >1.5 years and <2 years. Water levels higher than normal or up to bankfull conditions but no flooding is expected.

The river banks are colored according to river level legend (figure 6)

### DHMZ's Sava river catchment operational hydrological forecast

There is also a forecast model developed in DHMZ and Croatian Waters for river discharges and water level for the Sava catchmentin Croatia.

Figure 6: River water level forecast

## Forecasting area

The forecasting area is shown below (figure 7). City of Karlovac lays on 4 rivers Dobra, Kupa, Korana and Mrežnica. In this exercise two of them, Kupa and Korana (figure 8) are of interest to us.

Figure 7: Area of interest of the simulator

Figure 8: Rivers Kupa and Korana flow through Karlovac

* TECHNICAL NOTE: For the best interactive experience throughout this module please use the most recent versions of Firefox or Internet Explorer browser!