Trend and Homogeneity in Subsurface Hydrologic Variables: Case Study in a Hard-Rock Aquifer of Western India - Hydrologic Time Series Analysis: Theory and Practice - page 164

Kendall test for a linear and/or nonlinear trend (Salas, 1993), the Hotelling-
Pabst test (Conover, 1971), and the Sen test (Gilbert, 1987). Except one, all
these trend detection tests are discussed in Chapter 4 of this topic. A few more
rank correlation tests have also been suggested by Kanji (2001).
On the other hand, homogeneity implies that the data in the series belong
to one population, and hence have a time invariant mean. Non-homogeneity
arises due to changes in the method of data collection and/or the environment
in which it is done (Fernando and Jayawardena, 1994). Three homogeneity
tests, viz., the von Neumann test, Cumulative Deviations test and the Bayesian
test (Buishand, 1982) and four multiple comparison tests, viz., Tukey test,
Link-Wallace test, Bartlett test and Hartley test (Kanji, 2001) are most widely
used for exploring homogeneity in hydrologic time series. All these
homogeneity tests are described in Chapter 4 of this topic.
The main intent of this chapter is to demonstrate the application of time
series analysis to subsurface hydrologic time series viz., groundwater level
and net recharge time series. Trends and homogeneity have been examined in
these time series as well as in rainfall time series using the data of Udaipur
district, Rajasthan, western India. Udaipur district (study area) is situated in
the hard-rock hilly terrains of Aravalli Range in Rajasthan and suffers from
frequent droughts due to poor and delayed monsoon, low rainfall, abnormally
high summer-temperature and inadequate water resources (Bhuiyan et al.,
2006). Among consecutive five drought years (1998-2002), the 2002 drought
was one of the severest droughts in Rajasthan as well as in the history of India,
which affected 56% of the geographical area and the livelihoods of 300 million
people in 18 states (Samra, 2004). Thus, the study area is severely affected by
water scarcity, which has a direct impact on the livelihood, health and hygiene
of the inhabitants. Considering growing water scarcity and global climate
change, it is essential to examine trends and homogeneity in rainfall,
groundwater level and net recharge time series for the efficient management
of water resources in the study area. This case study also demonstrates the use
of geographical information system (GIS) in presenting the results of trend
and homogeneity tests.
8.2 Study Area and Data
The study area (Udaipur district) is situated in the southern part of the largest
and driest state (Rajasthan) of India (Fig. 8.1). It lies between 23°45 and
25°10 North latitude and 73°0 and 74°35 East longitude encompassing a
geographical area of about 12,698 km 2 . It consists of 11 blocks (viz., Badgaon,
Bhinder, Dhariawad, Girwa, Gogunda, Jhadol, Kherwara, Kotra, Mavli,
Salumber and Sarada). It is worth mentioning that for the administration
purpose, a state in India is divided into districts, districts into blocks and
blocks into Gram Panchayats ; each Gram Panchayat consists of several