eha_dmo.m

%% Eden Hazel interpretation.  
% This is a demonstration of the interpretation of Step-drawdown test with
% Eden and Hazel (1973) method 
%
% MIT License
% Copyright (c) 2017 Philippe Renard - University of Neuchâtel (CHYN)

%% Load the data
% The data set for this example where taken from: 
% Kruseman and de Ridder (1994) Analysis and evaluation of pumping test
% data, ILRI Publication No. 47, Table 14.1 page 204.
% 
% The original source of the data is:
% Clark, L. (1977) The analysis and planning of step-drawdown tests. 
% Quarterly Journal of Engineering Geology and Hydrogeology 10(2):125-143

%%
% Let us load the data in the matlab workspace with the ldf function.
% We then plot the data to verify them graphicaly.

[t,s]=ldf('eha_ds1.dat');
clf
plot(t,s,'o')
xlabel('Time in seconds')
ylabel('Drawdown in meters')
title('K data set')

%% 
% Hytool then needs to know the duration of the pumping steps and the 
% values of the pumping rates for each pumping step. This information
% is described and stored in a matrix made of two columns and as many
% raws as pumping steps. The first columns contains the time at which 
% the pumping stoped, the second the values of the pumping rates. 
%
% We need now to build this matrix and provide it to hytool.

qp=[1306 1693 2423 3261 4094 5019]/86400; % Vector of pumping rates in m3/s
tp=[10800 21600 32400 43200 54000 64800]; % Final time of each steps in s
q=[tp',qp'];                              % Build the required matrix 
eha_pre(t,q);                             % Initialize the eha model


%%  Model parameter identification and report
%
% We now fit the model and report the results as usual with hytool.

p0=eha_gss(t,s);
p=fit('eha',p0,t,s);
eha_rpt(p,t,s,'Theis interpretation of Kruseman and de Ridder data');

%%
% The estimated transmissivity is T = 2.5e-3 m2/s and the quadratic head 
% losses coefficient is B = 980 s2/m5. These numbers compare well with
% the values estimated by Kruseman and de Ridder (1994):
%
% T=3.1e-3 m2/d
% B=1.4e-7 d2/m5 = 1045 s2/m5