Center for Environmental Systems Research
University of Kassel
WAVES: Large Scale Water Management Modeling
          Modeling of water demand and technical water supply for water management in Piauí and Ceará

 Status Report VI
01-01-99 to 30-06-99

1) Project objectives

Objectives of our subproject in the first semester of 1999 were:

  1. to coordinate and intensify our work with the work of our recently financed Brazilian counterparts,
  2. to collect lacking data,
  3. to get an impression of the water quality situation in Ceará
2) Progress and results

a) Work progress

Crop-specific irrigation: The laborious creation and analysis of IBGE data on the irrigated area per temporary crop per municipality showed that there is no reasonable correlation between the total irrigated area per municipality and the sum of the harvested areas of irrigated temporary crops (Fig. 1) This discrepancy could not be explained even concerning multiple cropping. Lacking definite information we worked out two options for assigning the crop-specific irrigated area per municipality:

Figure 2 shows the correlation between the irrigated area assigned under option 1 and option 2. Comparing the NoWUM model results of the annual consumptive irrigation water use of option 1 and option 2 one can see that in 7% of all 332 municipalities the crop mix after option 1 or option 2 has no effect on the water use (Fig. 3). In 56% of all municipalities appears a bigger consumptive irrigation use under option 2 as under option 1 (up to 180 mm/a more). In 19% of municipalities the water use under option 1 is bigger. In the remaining 18% of municipalities consumptive irrigation water use is not significant.

Driving forces of future water use: Tab. 1 lists the factors of the five water use sectors in NoWUM influenced by scenario driving forces or being changed in water management scenarios, respectively.

Tab. 1: Influence factors of the five water use sectors in NoWUM
sector influences
households total population, population connected to public water supply, price elasticity, income elasticity
irrigation irrigated areas, irrigated crops, price?
livestock number of animals
industry price elasticity, industry mix, Industrial GDP, improving efficiency
tourism number of tourists, price 

Price and income elasticities: Having obtained 10-year time series of water tariffs, billed volumes and connections per municipal system (CAGECE) and GDP per municipality (IPLANCE), we are trying to determine the price elasticity and income elasticity of domestic water use in Ceará.

b) Cooperation

During our stay in Brazil in March and April, we agreed with Prof. Araújo (UFC) that his water costs project will supply our model with investment and O&M costs in the different water use sectors. During our common excursion with Prof. Araújo, two of his co-workers and A. Güntner (PIK) in the Jaguaribe valley, daily heavy rainfalls prevented a quantitative determination of water quality problems (Tab. 2). Prof. Vieira Pinheiro (UFC) consulted us with respect to the setup of his field study on the willingness to pay for public water supply in one community in the municipality of Tauá. It is not yet clear if his results are useable for us.

We continued and intensified our contacts to Brazilian organizations outside of WAVES (AGESPISA, CAGECE, COGERH, FUNASA, IPLANCE, SDU, SEAAB, SEAGRI, SEPLAN) who provided us with data and expert knowledge (see list of acronyms in Hyperwaves).

c) Dissemination of project results

First results of NoWUM were presented and handed over to the Brazilian waterworks AGESPISA and COGERH as well as to the Irrigation Secretary of Ceará (SEAGRI) and the Irrigation Department of the Agriculture Secretary of Piauí (SEAAB). We agreed on a seminar next year with CAGECE to present our analysis of their data and our model results.

Concepts and first results of WAVES water modeling were presented on a European Geophysical Society Symposium, April 1999, The Hague: Bronstert, A., Krol, M., Jaeger, A., Güntner, A., Hauschild, M., Döll, P. (1999): Integrated modelling of water availability and management in the semi-arid Northeast of Brazil. Ann. Geophysicae, 17, Suppl. II, Springer Verlag, (in press)

d) Workshops

3) Project management structure

The scenario group in which P. Döll participates worked out the final version of the two qualitative reference scenarios. They were basis for the scenario discussions during the workshops in Fortaleza and Teresina in April 1999.

4) Outlook

The final model structure of NoWUM will be handed over to the group Integrated Modeling in August 1999. We will then focus on developing and running scenarios of water use as well as of water management (in the integrated model).

A work plan for a second main phase of WAVES will be developed until the 1st of August. Concepts and results of WAVES water modeling will be presented at the "Deutscher Tropentag" in October in Berlin as a common presentation of all three German water groups.

5) Administrative aspects

We spend our whole international traveling funds for 1999 for the three-week stay of P. Döll (March) and the seven-week-stay of M. Hauschild (March and April) in Brazil. If the next international WAVES workshop will be held in Brazil already in 1999, we need additional traveling funds. The staff situation did not change in the first semester of 1999.


Fig. 1: Correlation between the total irrigated area per municipality and the sum of harvested areas of temporary irrigated crops per municipality.


Fig. 2: Correlation between the given total irrigated area per municipality (option 1) and the calculated irrigated area per municipality (option 2)



Fig. 3: NoWUM model results:
(1) Consumptive irrigation water use [mm/a] per total municipal area under average climatic conditions 1951-80 for irrigated areas of option 2.
(2) Differences [mm/a] between the consumptive irrigation water use of option 1 and the consumptive irrigation water use of option 2 under average climatic conditions 1951-80. Positive values mean that the water use of option 2 is higher than the water use of option 1. The longterm averages were computed as the mean of 30 years of simulation results.

Tab. 2: Probenahme Oberflächengewässer im Jaguaribe-Einzugsgebiet, März 1999 (Maike Hauschild und Petra Döll)
Nr. Datum Ort (Munizip) Flasche Nr. O2 [mg/l] Ammonium




pH* Leitfähigkeit*


O2 *


T *





1 18.3.99 Quelle des R. Granjeiro (Crato), aus Serra de Araripe, oberstrom Crato - 6.4 0 0 5.3 0.019 7.3 25.2 ?
2 18.3.99 R. Batateiras, abstrom der Stadt Crato (Crato) (A) 1 6.3 0.6 0 7.5 0.146 6.5 23.5 10
3 18.3.99 Ausfluß aus Barragem Padre Cicero, R. Batateiras, abstrom der Stadt Juazeiro do Norte (Juazeiro do Norte) 2 - 0.2-0.3 0 7.6 0.169 7.6 25.8 Dammlänge 80 m, Überfall 30 cm
4 18.3.99 R. Santanna, oberstrom Barbalho, unterhalb Zuckerrohranbau (Barbalho), im Zustrom zu Juazeiro do Norte 3 - 0.1 0 7.3 0.141 3.4 26.3 0.25
5 19.3.99 R. Salgado, vor Icó (Icó) 4 6.8 0.3 0 7.8 0.139 7.6 27.5 120
6 19.3.99 R. Salgado, in Icó, nach städtischer, ungeklärter Einleitung durch DNOCS (Icó) 5 6.3 0.3 0 - - - - 120
7 19.3.99 Entwässerungsgraben des DNOCS-Bewässerungsprojekts Lima Campos, viele Wasserpflanzen, Colonos, gemischter Anbau (Lima Campos) 6 + Pest. 1 - 0.1 0 - - 3.4 - 0.1
8 20.3.99 R. Banabuiu, Brücke der BR, Abfluß des Bewässerungsgebiets Banabuiu (Limoeiro do Norte) 7 + Pest. 7 - 0.5 10 - - 4.6 - -
9 20.3.99 Entwässerungsgraben im Bewässerungsperimeter Morada Nova, Zufluß zu 8 (Limoeiro do Norte) 8 - 0.3 0 - - - - -
10 20.3.99 Entwässerungsgraben im Bewässerungsperimeter Morada Nova, kleiner als 9, Zufluß zu 8 (Limoeiro do Norte) - - 0.1 0 - - - - 0.2

* mit Sonde gemessen, Rest per Schnelltest
(A): laut Anwohner stinkt der Fluß in der Trockenzeit
jeweils oberflächliche Probenahme
Beprobung in Regenzeit, starker Regen an allen Tagen, bei Probenahme Nr. 6 Starkregenereignis bis ca. 1/2 h vor Probenahme.