Data used and interpreted parameters.
In the coastal aquifer of the lowlands on the right side of the river Sinaloa there is need for fresh water for agricultural development since, around 15% of the water used in agricultural irrigation, is from underground sources. This situation is exacerbated in periods of drought, which promotes drilling with the risk of finding brackish water in them; besides, there is the risk of not meeting water demand due to low hydraulic transmissivity (T) of the aquifer, putting at risk the drilling costs that this implies. In this sense, the determination of T and K (hydraulic conductivity) is important for the development and management of groundwater exploitation of the study area. Generally by means of pumping tests in wells, T is obtained, with high costs, so there are few values of T. K is generally obtained by wells and laboratory test. The aim of this chapter is to establish an empirical relationship between T and K with Dar-Zarrouk parameter in porous media, transverse resistance (T R ), in addition to a characterization of the water quality through the electrical resistivity. This parameter is estimated from surface resistivity measurements, which are more economical in relation to the pumping tests; thus, T was characterized in the study area. The coefficient of correlation of the exponential adjustment is 0.79 and the relation is T=137185.7 TR0.020758−156691 and K=367.210.0548−518.813 with coefficient of correlation of 0.678.
- electrical resistivity
- water quality
- transverse resistance
- hydraulic transmissivity
- hydraulic conductivity
Groundwater of the coastal aquifer in the lowlands of the right side of the Sinaloa River constitutes an important support element for the development of agricultural activity in the region, especially during periods of drought. In order to extract groundwater, it is necessary to perform perforations, whose costs are high. In addition to the high cost is the uncertainty of finding fresh water, so it is desirable to have a preliminary characterization of the quality of groundwater, as well as the hydraulic property, which defines the aquifer water production. Hydraulic transmissivity (
Niwas and Singhal  found analytic relationship between the parameters of Dar-Zarrouk and
Ponzini et al.  found an empirical function between the transversal electrical resistance of an aquifer with its T. The shape of the relation between aquifer properties and geophysical parameters can be linear or non-linear . The empirical function found is of the potential type of the form
2. Materials and methods
2.1. Description of the study area
The study area is located between the coordinates 25°16′50″ and 25°41′13″ north latitude and 108°24′51″ to 108°41′22″ west longitude (see Figure 1). The climate is dry, very warm, and warm with rains in summer. The average annual precipitation is 300–400 mm (1986–2013) . The average annual temperature is 22–24°C for the 1986–2013 series . Soils are of alluvial origin, Cenozoic era, quaternary period, predominating soils Vertisol (62.55%), Solonchak (21.72%), Cambisol (3.17%), Kastañozem (2.58%), Regosol (2.13%), Phaeozem (1.52%), Arenosol (1.24%), Fluvisol (0.92%), and Leptosol (0.56%) .
The topographical relief is smooth, has a gradient that goes from 0.5 to 1 m per kilometer in a northeasterly direction (Figure 2). This was obtained from the heights of the ledge of the wells.
2.2. Wells information
Thirty wells were analyzed with a depth between 100 and 150 m, which were built by the National Water Commission. The wells are geotagged with a portable GPS brand Magellans. Water samples were obtained from each well; for this the wells in operation were sought, and groundwater electrical conductivity was measured
The interpretation of the pumping tests indicated that 3.3% of the
The Theis method presupposes that the well crosses the whole aquifer. In this case, the correction was not made, because at the moment, neither with geophysics nor with the columns of the wells, the total thickness of the aquifer is known. On the other hand, the impact of the lack of correction is insignificant, since the observed descents are less than 15% of the total saturated thickness, that is, the thickness is greater than 150 m and the observed descent is less than 10 m; thus, according to  it is not necessary to make the correction to Dupuit when the descents are inferior to 15 by 100 of the initial saturated thickness,
2.3. Aquifer geometry
With the information of the 30 lithological columns of wells, the geometry of the aquifer of the study area was determined. Figure 3 shows a section with the sequence of materials where an abundance of gravel with silty clay matrix, standing out in the presence of a body of gravel is seen. The lithological columns of the wells that have depths between 100 and 150 m do not show a geological or hydrogeological basement.
2.4. Vertical electrical soundings
Fourteen wells were selected from 30 wells. In these, a vertical electrical survey was carried out, having them as the center of the sounding. The Schlumberger array was used with a maximum current electrode separation of 500 m the soundings were interpreted by direct modeling using the Guptasarma algorithm .
2.5. Relation between
R wand R o
With the modeling of the vertical electrical sounding, the resistivity (
3. List of hydrological parameters (
Tand K) with geoelectric measurements and pumping tests
With information from true resistivity (
4. Results and discussion
4.1. Geoelectric sounding
Figure 4 shows the result of the VES performed in wells 1 and 10. For the modeling of the VES data, the available information of the lithological columns, static level of the water, and its salinity was considered. Experimental data and their corresponding models, as well as the root-mean-square (RMS) error of each adjustment are presented. The lithological relationship with electric resistivity allows delimiting the aquifer area, characterized by predominantly low clayey materials. In the case of well 1, the electrical resistivity was 13.04 Ω-m, and in the case of well 10, it varied from 9 to 29 Ω-m. The presence of materials with clay wells favors the
4.2. Water quality
Some authors [11, 28–30] have successfully applied the Archie’s law to hydrogeology studies. Figure 5 shows the fit for 14 pairs of
The practical meaning of this relation is that, if it is desired to perform a perforation in the study area, it is possible to perform a vertical electrical sounding prior to drilling; its interpretation can be determined by
With the value of the EC and considering the relationship between EC and total dissolved solids (TDS), salinity can be obtained by the expression 
With the value of TDS, the type of water expected can already be determined . From the interpretation of the VESs, it was found that the resistivity of the aquifer formation
|Well number||Well depth||Porewater resistivity (||Hydraulic transmissivity (m2/day)||Hydraulic conductivity (m/day)||Computed parameters—VES interpretation|
4.3. The relationship between
Tand T R
Other authors have found direct linear relationship: Niwas and Celik  assumed that the product
4.4. The relationship between
Kand T R
Measurements of aquifer resistivity are useful to estimate the aquifer hydraulic conductivity due to the fundamental relation between K and electrical conductivity . Kelly  worked with glacial outwash materials and obtained a linear connection between resistivity and K in relatively uniform water quality. The exponential relation allows to correlate
Exponential relations between geohydrologic parameters (
Our gratitude to the General Direction of Research and Post graduate of the Autonomous University of Sinaloa for supporting the Project and generating the suitable conditions to fulfill the present work.