APPLICATION OF LOW-COST SENSORS FOR THE DETECTION AND ASSESSMENT OF HYDRO-METEOROLOGICAL EXTREME EVENTS

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Flash-flood Spitzkunnersdorf – 14.05.2017

Flashfloods in small catchments – difficult to monitor

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Spitzkunnersdorf Size of catchment ca. 8km²

Nearby DWD weatherstations: 6km Hörnitz 14km Dürrhennersdorf 19km Ostritz

Overview

Research group @ TUD; funded by European Social Fund

3-years project; 07/2016 – 06/2019

8 researchers (5 PhD, 3 PostDoc) from 4 disciplines (Meteorology, Hydrology, Photogrammetry, Geoinformatics)

Main goals:

Monitoring and analysis of flash flood events in small and medium-sized catchments

Development of new tools for the prediction of flash floods

Development of strategies and methods for collaborative information and early warning systems

EXTRUSO Project (Extreme events in small and medium sized catchments)

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Meteorology

Soil moisture analysis and prediction

High-res. precipitation from radar

Hydrology

Hydrological modelling

Data-driven modelling

Flash-flood prediction

Photogrammetry

Low-cost camera-based monitoring of W and V

Topogr. measurements from UAV and UWV

Geoinformatics

Low-cost precipitation measurements

Online information system

Citizen engagement strategy

Subtasks by Discipline

Workflow

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Acquisition of hydro-meteorological

parameters

Provision of hydro-meteorological time

series

Acquisition of hydro-morphological

parameters

Hydro-meteorological

modelling

Information infrastructure

Basic Idea:

• Camera takes a sequence of images

• Automatic water line extraction

• Re-projection of the extracted line into object space

retrival of water level

• Measured control points needed

• DTM needed

TLS of test site

Low-cost camera-based monitoring of waterlevel and velocity in small rivers

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waterline

• Low-cost system based on Raspberry Pi Zero + Raspberry Pi camera

• Witty Pi Add-on Board (RTC) for energy saving

• Scripts for waterline extraction running in python

• User interaction still needed

If you have further questions

anette.eltner@tu-dresden.de

Low-cost camera-based monitoring of waterlevel and velocity in small rivers - Implementation

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Several sensortypes have been tested:

• eTape Fluid Level Sensor

• Grove Water Sensor

• Microphones

Low-cost precipitation measurements – Sensortypes I

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Tipping Rain Gauges:

• Different models - prices ranging from 15€ - 80€

• Davis Tipping Rain Gauge chosen for further testing

Low-cost precipitation measurements - Sensortypes II

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Long-term calibration of Davis rain sensor

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• Sensor was installed at the Tharandt Climate Station (TUDD)

• time series 06.06.17 – 14.08.17

• Coefficient rain / tip can be tweaked to minimize difference

Rain Gauge Davis Rain Sensor

Young Tipping Gauge

Ott Pluvio TRwS 200

Price ca. 80€ ca. 600€ ca. 8000€ ca. 3000€

Type Tipping Gauge Tipping Gauge Weighing Gauge

Weighing Gauge

Sum TS 159,2 mm 169,2 mm 173,0 mm 174,2 mm

Difference Ensemble

- 12,9 mm - 7,5 %

- 2,9 mm - 1,7 %

+ 0,9 mm + 0,5 %

+ 2,1 mm + 1,2 %

• Raspberry PI Zero W

• UMTS Module

• Raspberry PI Camera

• Battery + Solar Panel and Charging Electronics

• read Sensor

• run from battery / solar panel

• upload measured data

• Integrate with camera based system

• Low-cost

Requirements for gauging station and chosen hardware

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Power consumption

Raspberry PI Zero W idle / logging 0.75 – 1.00 W

RPi + UMTS Modem standby 1.50 – 2.00 W

RPi + UMTS Modem active 2.50 – 3.00 W

RPi + Camera module active 2.55 – 3.00 W

Considerations on saving energy

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Pi should run only when needed Arduino Pro Mini used as Controller to switch Raspberry Pi on if needed. UMTS / Camera only active when needed Scripts on Raspberry PI switch on UMTS / Camera if needed Power consumption if switched off: 0.05 W

Design of prototype

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Item Price

Raspberry PI Zero W 10€

Raspberry Camera Module 25€

Davis Tipping Gauge 80€

Groove Rain Sensor 3€

Real Time Clock 3€

UMTS Module 10€

Battery (12V 7Ah – 84Wh) 15€

Solar Panel + Charging Controller (50 WP) 75€

Electric components, housing 15€

Total Ca. 236€

Low Cost ?

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• water level and precipitation can be measured in good quality with low-cost sensors

• cost of a single station is low compared to professional rain sensors or water level gauges

• Price still too high for a dense permanent network

Ad-hoc use for events predicted by radar forecast and Hydro-meteorological modelling

Citizen engagement

Conclusions - Operational scenario

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