ARC GIS IN THE SANTA RIVER BASIN

IN PERU

The Highest Point of the Santa River Basin is Huascaran Snow – Capped

EUSEBIO INGOL

The University of Texas at Austin

GIS in Water Resources

Dr. David Maidment

Fall 2006

FINAL PROJECT

Content 1. Introduction2. Objectives3. Methodology

3.1 Study Area3.2. Data Sources3.3. Working with Geographic Information Systems (GIS)

4. Watershed and Stream Network Delineation4.1 Terrain Processing 4.1.1 DEM Reconditioning 4.1.2 Fill Sink4.1.3 Flow Direction4.1.4 Flow Accumulation4.1.5 Stream Definition and Segmentation 4.1.6 Catchment Grid Delineation 4.1.7 Catchment Polygon, Drainage Line, and Drainage Point Processing

4.2 Watershed Processing4.2.1 Batch watershed delineation 4.2.2 Batch Sub Watershed Delineation

5. Spatial Analysis 5.1 Contours5.2 Slope

6. Application of Arc Hydro7. Localization of Precipitation Stations

7.1 Estimation of the Precipitation7.1.2 Monthly Mean Precipitation for 17 stations7.1.3 Monthly Mean Precipitation for the Sub Watersheds7.1.4 Annual Mean Precipitation for the Sub Watershed

8. Analysis of Discharge in the Stream Gage Condocerro.8.1 Analysis of Persistence

9. Conclusions

1

ARC GIS in the Santa River Basin in Peru

1. Introduction

Nowadays, in many places of the world, there is competition for water resources

because the population is increasing every day which means a major production of foods

and consumption of the available water resources. Additionally, the distribution of water

is very irregular in space and time. This problem demands the use of tools that allow

planners to improve the use of water resources in their respective regions. One of the

most important tools that can be used to that end is Geographic Information Systems

(GIS). This system enables to store and to analyze spatial information for being used later

with other models of water resources.

Maidment (2002) reported that many databases are available on the internet such

as climate variable, soil, land cover, gaging stations, and these can be processed in GIS.

In addition, he mentions that GIS has been converted in an important tool for hydrologic

modeling, and it uses Digital Elevation Model to delineate watersheds and stream

network. In that sense, hydrologists use several data sources to evaluate water quality,

quantify water allocation, avoid flooding, plan and operate water resources systems, and

interpret environmental problems. Likewise, specialists and people involved in water

resources that use Geographic Information Systems (GIS) as a tool and database are

increasing; therefore, GIS is being accepted as a powerful tool for storing spatial

information (Maidment 5).

In this context, this project presents an application of Arc GIS in the Santa River

system in order to generate information and calculate the precipitation and runoff

respectively. The Santa River Basin is located in the department of Ancash in the North

of Peru and is one of the most important of the Pacific Ocean basins in that country.

2. Objectives

The main purpose of this project is to apply Arc GIS for generating a database to

the Santa River Basin in Peru, as well as the following specific objectives:

- Delineate watershed and streams.

- Calculate the Precipitation in the watershed.

2

- Analysis the runoff in the Condocerro Station.

- Determine some parameters of the basin of study

3. Methodology

3.1 Study Area

This project is focused on the Santa River Basin, which is located the department

of Ancash in the North Peru, between the parallels 10 15’ and 07 55’ Latitude South and

Meridians 78 45’ and 77 05’Longitude West. The general location can be seen in Figure

1.

Figure 1 Localization of the study zone

3.2. Data Sources

Getting information or databases in Peru for researching is a little difficult;

however, we can get data from internet, information available for the world such as the

USGS 3 arc-second Digital Raster Elevation and coverage of the Digital Chart of the

World (http://www.maproom.psu.edu/dcw/ ). The USGS provides seamless SRTM

(Shuttle Radar Topographic Mission, http://srtm.usgs.gov) finished with a 3 arc second

(90 meters position) digital elevation raster that covers almost the entire globe. These

facilities allowed downloading a SRTM date for the study zone in which coordinates

were entered. Moreover, flow line files for the Santa River Basin was collected of the

Irrigation District Santa – Nepena – Lacramarca in Peru. This file was imported to a

3

personal Geodatabase as feature class (single) for which we used ArcCatalog. It is

necessary to indicate that the file of flow lines allowed us to do the DEM reconditioning.

The files unzipped of the Digital Elevation Raster are the following:

47457215.aux, matadate.shp, dbf, prj, and shx, folder 47457215 with bblbnd.adf, hdr.adf,

prj.adf, sta,adf, W001001.adf, x.adf, and a folder with files arc 0000.

The DEM for the river basin in study is shown to continuation whose geographic

coordinates are:

Parallel: 10 15’ and 07 55’ Latitude South

Meridian: 78 45’ and 77 05’ Longitude West.

Legenddem_peruValue

High : 6687.000000

Low : -27.017836 Figure 2 SRTM for the Santa River Basin in Peru

4

Additionally, information coordinates of 17 stations with average values of rainfall (1956-

1980) and the average discharges in the Condocerro Station (1956-2000) were obtained.

This information was given by two professionals in Engineering Carlos Cruzado and

Alejandro Junes who work in the irrigation districts Santa – Lacramarca and Casma –

Huarmey in Peru respectively.

3.3. Working with Geographic Information Systems (GIS)

The first step was adding the original SRTM data containing the Digital Elevation

Model for the Santa river basin to ArcMap. The coordinate system of these data was

converted from geographic systems to a projected geographic system, using ArcToolboox

( Data Management Tools, projections and transformations , raster, project raster) in

ArcMap. The projected coordinate system selected was the Universe Transverse

Mercator (UTM) because it is a coordinate system that is more adaptable to the study

zone. Likewise, the Cubic Convolution method was used to determine the new cell

values, and the output cell size was 90 m because the SRTM data is at 3 seconds of

resolution which means approximately 90 m of spacing.

Before applying the DEM reconditioning, we created a mask in order to work

only in the study area. For this end, we used the Arc Map tools to generate a buffer whose

input feature was the Santa file (preliminary delimitation), and output feature class called

Santa Buffer; moreover, the linear unit was defined as 6 km. After that, we were ready to

extract by mask the information of this area for which the input raster was the DEM, the

feature mask data was the Santa buffer, and the output raster was Santa DEM. Figures 3

and 4 show the Buffer and DE for the Santa River Basin.

5

Figure 3 Buffer for Santa River Basin Figure 4 SRTM for Santa River Basin

The exercises 3, 4, and 6 of the GIS’s course in the University of Texas at Austin in the

Department of Civil Engineering were the base for developing this term project. The

methodology in Arc GIS can summarize in the following way:

1. Download the DEM on the website for the Santa River Basin.

2. Add this DEM to Arc Map, and convert the geographic coordinates to projected

coordinates system.

3. Create a buffer for only working in the study area.

4. Apply Hydro Tools, specifically the Menu terrain processing to prepare the spatial

information.

5. Delineate the watershed and sub watersheds in the Santa River Basin. For this

end, we use the menu Watershed Processing in Arc Hydro Tools. In this part, we

created a bath point in the Outlet of the basin in order to delineate it. After that,

we delineated sub watersheds for which we used the sub menu batch

subwatershed delineation.

6. After that, calculate some parameters of the basin such area, slope, contours,

length of streams, flow paths, etc.

6

7. With the information generated, we applied the Arc Hydro with times series for

the Santa River Basin. For this end, we used Arc Catalog to create a geodatabase

called Santa _ArcHydro. After geo reference and apply the scheme to the Arc

Hydro feature dataset, we populated the feature classes with the information

obtained in prior process. Likewise, we did not load data in the feature class water

body because we did not have information about it. For the Hydro junction

features class, we used as points junctions the outlet on the basin and the

condocerro station; we did not use the points of the stations of precipitation

because those are out the river and not constitute junctions.

8. For estimating the precipitation in the sub watersheds, we used the Thiessen

polygon method in ArcGIS. The tool that allows doing this procedure is Spatial

Analysis (distance, allocation). Moreover, we created a file in format txt in order

to reclassify the grid obtained. After that, we used Spatial Analysis – Reclass by

ASCII File.

9. The information stored in the times series in Arc Hydro was exported to excel in

order to do an analysis of the runoff in the Condocerro station. We used the

Weibull Method for plotting the Flow Duration Curve.

4. Watershed and Stream Network Delineation

4.1 Terrain Processing

In this part, the objective was to prepare the spatial information of the Santa River

Basin for the subsequent use. The Digital Elevation Model was processed using Arc

Hydro Tools 9 in ArcMap – ArcInfo. First, we used the menu terrain process in order to

prepare the information for the watershed processing. In that sense, the application of this

tool allowed to generate information of flow direction, flow accumulation, stream

definition, stream segmentation, drainage lines, and watershed delineation for the Santa

River Basin.

The SRTM downloaded from the web site had many holes which made it difficult

to recondition the DEM in order to use with other applications; for this reason, it was

rebuilt using the ArcGIS tools.

7

4.1.1 DEM Reconditioning

Once the area was specified, we did the DEM reconditioning which is a AGREE

method developed by the Center for Research in Water Resources at the University of

Texas at Austin. This method allows adjusting the surface of elevation of the DEM to be

consistent with vector coverage (Maidment, 1997). For this case, we used the stream lines

coverage of the Santa River Basin as linear features. The area reconditioned is shown in

Figure 5.

Figure 5 AGREE DEM for the Santa River Basin

4.1.2 Fill Sink

It is very common to find cells in a DEM with low elevation enclosed by other

cells with high elevation. These low cells are called sinks, which may be formed by the

landscape features or errors during the DEM generation as well as by the limited

resolution of the digital elevation model. The sink is filled until it will drain the water to

8

the next lowest point. For this end, we can execute “fill Sink” in Arc hydro tool in Arc

Map.

4.1.3 Flow Direction

The flow direction for the Santa River Basin was determined for the filled DEM,

which is one of the most important for generating the hydrologic characteristics of the

river basin. In Arc Map, the flow direction function calculates the direction of the flow

out finding the direction of the steepest descent from each cell in the grid. There are eight

output directions in which the flow of a cell can move. The direction of flow for the Santa

River Basin is shown in figure 6.

Figure 6 Flow Direction Grid for the Santa River Basin

9

4.1.4 Flow Accumulation

The flow accumulation for the Santa river basin was calculated taking as base the

flow direction. Its procedure consisted of calculating the accumulated flow for each cell

as the weight of each of them that flows through down slope. In other words, the output

of the flow accumulation represents the amount of water that would flow through each

cell. Moreover, it was the base to create the drainage lines. We can see the flow

accumulation for the river basin in figure 7, and a detail for it is presented in Figure 7.1.

Figure7 Flow Accumulation Grid for Santa River Basin

10

Figure 7.1 Detail of Flow Accumulation Grid

4.1.5 Stream Definition and Segmentation

The definition of streams for the river basin was made considering a threshold of

1000 cells of 90 x 90 m, which means an area of 8.1 km2 for catchment definition. In

other words, this was the threshold drainage area to generate a stream in the study basin.

After the definition of streams, a grid of stream segments was created using the function

stream segmentation in Arc Hydro Tool. In Figure 8 is shown the stream definition for

the basin of study.

11

Figure 8 Stream definition

4.1.6 Catchment Grid Delineation

This function in Arc Map allowed the creation of a grid for the segments in the

stream link grid (stream segmentation). Moreover, it identified the drainage areas into

each stream link. The generated catchments are presented in Figure 9.

12

Figure 9 Catchment Grid Delineation

4.1.7 Catchment Polygon, Drainage Line, and Drainage Point Processing

These functions allowed converting the raster date to a vector format. Catchment

polygons were created from the catchment grids, and drainage lines were created by

converting the stream link grid into a drainage line feature. For this case of study, we

created 1311 catchments, and a drainage line belongs for each of them. The Catchment

polygon and drainage line processing are shown in Figures 10 and 11 respectively. In

Figure 12, we can see the drainage points generated for the basin of study.

13

Figure 10 Catchment polygon processing

14

Figure 11 Drainage Line Processing

15

Figure 12 Drainage point processing

4.2 Watershed Processing

This part of the project consists of delineating the watershed and sub watersheds,

as well as determining the flow path in the river basin. Arc Hydro in ArcMap was used

to carry out this process.

4.2.1 Batch watershed delineation

The watershed was fundamentally delineated by the drainage lines, accumulated

flow, flow lines and the preliminary delimitation of the river basin. First, we created an

outlet point on the flow accumulation path where the flow leaves the Santa River Basin

which in this case, the point is very close to the Pacific Ocean. For this end, the button

Batch Point Generation in Arc Hydro was used. This point can be used as an input to the

16

bath watershed and sub watershed delineation functions. The drainage area of the

delineated watershed is 12, 166.81 km2. The result obtained of this process can be seen in

Figure 13

Figure 13 Delineated Watershed for Santa River in Peru

4.2.2 Batch Sub Watershed Delineation

Sub watersheds are divisions based upon the drainage area divided on a

watershed. In this part, we created a subwatershed for every point in the bath point

feature class, and the result was stored in a subwatershed feature class. For this study, we

did not have information about gaging sites to determine the sub watersheds. In that

sense, sub watersheds were delineated by considering three very important points in the

17

river basin. Two of them are located on higher ground of the basin through which the

major amount water resources drain from those sub watersheds. Another point is located

in the outlet of the Santa River Basin, and it defines the sub watershed in the lowest

altitude. Once the watersheds have been defined, they were used as measurement areas

to calculate different parameters. The drainage areas are 1,775.35 km2, 3,180.40 km2,

and 7,211.06 km2 for the sub watershed Santa – Outlet, Tablacacha, and Anta

respectively. The result of the delineation the sub watershed can be seen in Figure 14.

Likewise, in Figure 15 is shown the goedatabase generated for the Santa River Basin.

Figure 14 Delineated Sub Watersheds for Santa River Basin

18

Figure 15 Geodatabase for the Santa River Basin

5. Spatial Analysis

5.1 Contours

The contours were calculated with the Spatial Analysis tool in ArcGIS. The input

surface was the DEM Santa with a contour interval 50 m. In figure 16 can be seen a

detail of the contours for the Santa River Basin.

19

Figure 16 Contours for the Santa Basin

5.2 Slope

The mean slope calculated for the watershed was 3 %. For the sub watersheds the

values of mean slope were 1.07 %, 3.2 %, and 3.8 % for Santa – Outlet, Tablacacha, and

Anta respectively.

6. Application of Arc Hydro

Independently of the lack data, with the information generated for the Santa River

Basin is possible to apply Arc Hydro with time series in order to do several analysis of

hydrologic data. First, we created a Geo Database called Santa_ArcHydro.mdb; and after

that applied the Arc Hydro scheme to this geodatabase. This scheme is a XML file that

describes the features classes, fields, tables, and relationship defined in the Arc Hydro

20

with time series. The coordinate system for the Archydro feature dataset was imported of

the Hydro feature dataset located in riosanta geodatabase. Likewise, the hydroNtwork

was deleted because we needed to rebuild a new geometry network later. After that, the

features classes from ArcHydro Santa were populated with date from features classes

generated in the first part of this term project. It is necessary to indicate that the feature

class water body was not populated because we did not have information about it. You

can find the methodology more detailed about this procedure on the website

http://www.ce.utexas.edu/prof/maidment/giswr2006/Ex6/Ex62006.doc

In the following figure, we can see the Arc hydro for the Santa River Basin as

well as time series for the Condocerro Station.

Figure 17 Arc Hydro with Times Series for the Santa River Basin

Hydro junctions and hydro edges for the Santa River can be seen in figure 18, and in

Figure 19 is shown the direction of flow.

21

Figure18 Hydro Network Santa Junctions

22

Figure 19 Direction of Flow in the Santa River Basin

The Longest flow for the Santa River is shown in Figure 20. It has an approximate length

of 342 km and through a drainage area of 8,986 km2 in the Santa –Outlet and Anta

watersheds respectively.

23

Figure 20 Longest Flow Path in the Santa Basin

7. Localization of Precipitation Stations

In this part, the geographic coordinates of each station were located on the map.

For this end, we built a table in Excel with the respective coordinates. This information is

saved in a file with name LonLat in format DBF4 (dBASE IV). After that, open ArcMap

and add the file that contains that table. In ArcMap, this table was converted to feature

class and located in the geodatabase Santa. You can see the following windows:

24

The feature class created was StationSanta such you can see in the window

above. In this feature class, we added more fields such as the name of station, annual

precipitation and other. The map generated can seen been in Figure 21.

Figure 21 Localization of stations of precipitation

25

7.1 Estimation of the Precipitation

The annual mean precipitation for each sub watershed was calculated with the

Thiessen Polygons in Arc GIS. These polygons define particular areas of influence

around of each station in the basin.

7.1.2 Monthly Mean Precipitation for 17 stations

The variation of the monthly mean precipitation for the period 1956-1980 can be

seen in Figure 22. The monthly values vary from 0 to 143 mm whose minimum values

during the year are presented in Rinconada station located in the cost from Peru. It is

necessary to indicate that Peru has three regions very different: Cost, Mountain, and

Jungle. The major amount of rainfall is produced in the Mountain and Jungle. Most in the

Coast, the precipitation is minimum (below 10 mm by year) with exception in the North

(departments of Piura and Tumbes) where there are a considerable precipitation during

the year.

Average Rainfall in the Santa River BasinPeriod 1956-1980

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

160.00

180.00

San

tiago

de

Chu

co

Mol

lepa

ta

Con

chuc

os

Cor

ongo

Par

on

LaR

inco

nada

Car

az

Llan

ganu

co

Yun

gay

Cha

ncos

Hua

raz

Qui

roca

ncha

Rec

uay

Tica

pam

pa

San

Lor

enzo

Pac

haco

to

Que

roco

cha

Stations

Rai

nfal

l (m

m)

JanFebMarchAprMayJunJulAugSepOctNovDec

Figure 22 Mean Precipitation in stations of the Santa River Basin

7.1.3 Monthly Mean Precipitation for the Sub Watersheds

In Figures 23 and 24, we can see the monthly average rainfall for the sub

watersheds Tablacacha and Anta. The Santa – Outlet sub watershed only shows values to

the Rinconada station because we do not have information for calculate the average

26

precipitation. Theses values correspond to the period 1956-1980. Moreover, we can

observe that in the months of June, July, and August the precipitation is minimal. In the

period from January to April occurs the most important rainfall in study zone. The

behavior is similar in both subwatersheds; being totally different in Rinconada station

which is located in the coast from Peru (Figure 25).

Monthly Mean Precipitation for the Sub Watershed Tablacacha. Santa River Basin in Peru.

Period 1956-1980

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

Jan Feb March Apr May Jun Jul Aug Sep Oct Nov Dec

Months

Prec

ipita

tion

(mm

)

Figure 23 Variation of monthly precipitation in the Tablacacha subwatershed (Mountain

from Peru)

27

Monthly Mean Precipitation for the Sub Watershed Anta Santa River Basin

Period 1953-1980

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

Jan Feb March Apr May Jun Jul Aug Sep Oct Nov Dec

Months

Prec

ipita

tion

(mm

)

Figure 24 Variation of monthly precipitation in the Tablacacha Anta (Mountain from

Peru)

Monthly Mean Precipitation for the Rinconada Station. Santa River Basin

Period 1956-1960

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Jan Feb March Apr May Jun Jul Aug Sep Oct Nov DecMonths

Prec

ipita

tion

(mm

)

Figure 25 Variation of monthly precipitation in the Rinconada station (Coast from Peru)

28

7.1.4 Annual Mean Precipitation for the Sub Watershed

Thiessen Polygon method allowed determining the annual mean precipitation for

each watershed. The total precipitation for the basin is 1232. 50 mm which 593 mm

correspond to the Anta sub watershed, 568 mm to the Tablacacha sub watershed, and 71

mm to the Santa – Outlet. The volume of precipitation in the basin is around

M3 or CFS. Figure 26 shows the annual precipitation for each sub watershed.

Likewise, in Figure 27, we can see the distribution percentage of the volume of

precipitation for each sub watershed. The 98 % of this volume is derived of the Sub

watershed Anta and Tablacacha.

91021.6 x111021.2 x

Figure 26 Annual Precipitation in the sub watersheds in the Santa River Basin

29

Figure 27 Distribution of volume of precipitation in the Sub watersheds

8. Analysis of Discharge in the Stream Gage Condocerro.

The values stored in time series in Arc Hydro were exported to Microsoft Excel

for doing the respective analysis of discharge of the Condocerro station. This station is

located very close to the outlet of the sub watersheds Tablacacha and Anta which were

delineated in this study. The Figure 28 shows the annual and monthly mean discharge for

a period 44 years (1956-2000) in the Condocerro station. The values vary between

85m3/s and 225m3/s in average. Additionally, in the graphic of monthly discharges, we

can observe three periods very important in this river basin. The first period can define

from January to April; period in which is produced the maximum flow in the river, and it

coincides with the most important precipitations in the sub watersheds Anta and

tablacacha (part high of the basin). The second period starts from May to September in

which the rainfall is minimal which means minor discharges. The third period covers

from October to December; period in which observes discharge above 80 m3 /s and

where begin the precipitations in the high basin. Despite the fact that in the period June to

August there is not rain in the basin, we can observe important discharges in the river.

This behavior is due to the incidence of thaws of the White Mountain, which contributes

to maintain a considerable amount of water in this period.

30

Figure 28 Monthly and annual mean discharge in the Condocerro Station. Santa River

Basin

8.1 Analysis of Persistence

The information of discharge for the period 1956 to 2000 in the Condocerro

station allowed doing an analysis of flow duration curve, which is a plot that shows the

percentage of time that flow or discharge in the Santa River was probably equaled or

exceeded. For this end, we ranked the discharge values in ascending order; after that,

applied the following Weibull formula:

1001

xnmP+

=

Where, P is the probability of all events less than or equal to each discharge value, m is

the rank of the event, and n is the number of events on record. The Figure 29 shows the

flow duration curve for the Santa River.

31

Flow Duration Curve for the Santa RiverStation Condocerro (1956-2000)

y = 211.03e-0.0087x

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

160.00

180.00

200.00

220.00

240.00

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

Porcentage of time

Dis

char

ge (m

3/s)

WeibullExpon. (Weibull)

Figure 29 Flow Duration curve in the Condocerro station in the Santa River Basin

This flow duration curve permits to calculate the discharges of the Santa River

that occurs or exceeded some percentage of the time. It will be very useful for the

management and development of water resources in the basin of study. Some values can

be seen in the table 01.

Porcentage Dischargeof time m3/s

50 135

75 11090 96

Table 01 Discharge estimated with flow duration curve

32

9. Conclusions

Based on the watershed and stream delineation with the Geographic Information systems,

we conclude the following:

1. Arc Hydro in ArcMap is a powerful tool for delineating and organizing information

data in river basins where databases are not available. This project shows the possibility

of using information available on the internet and processing it with Arc Hydro in order

to generate and store data that will contribute finally to improve the operation and

planning of the water resources systems.

2. The drainage area calculated for the Santa River Basin was 12166.7 km2 with a length

of streams of 3157.45 km. Likewise, the density of drainage is 0.26 / km.

3. The delineated watersheds were Santa-Outlet, Tablacacha, and Anta.

4. The sub watersheds Tablacacha and Anta are the main source of water resources in the

basin, whose annual precipitation estimated were 568 mm and 593 mm respectively.

5. Based on the analysis of discharge, we conclude that for a 75 % of persistence, the

annual mean flow will be 110 m3/s which means an annual available volume around

m3. This volume comes from the sub watershed Anta and Tablacacha. 910469.3 x

6. The mean slope of the Main River is 0.012, and the streams are 0.088

33

Acknowledgements

Dr. David Maidment

Dr. Deane Mckinney

Dr. Carlos Patino

Ing. Carlos Cruzado from Peru

Ing. Alejandro Junes from Peru

Bibliography

Digital Chart of the World Server. Pens State University Libraries.

http://www.maproom.psu.edu/dcw/

Maidment, D. 2002. Arc Hydro-GIS for Water Resources. ESRI Press. Redlands,

California.

Maidment, GIS in Water Resources Fall 2006

http://www.ce.utexas.edu/prof/maidment/giswr2006/Ex3/Ex32006.mht

http://www.ce.utexas.edu/prof/maidment/giswr2006/Ex4/Ex42006.htm

http://www.ce.utexas.edu/prof/maidment/giswr2006/Ex6/Ex62006.htm

USGS, Shuttle Radar Topography Mission.

http://srtm.usgs.gov/

Figures Figure 1 Localization of the Zone of StudyFigure 2 SRTM for the Santa River Basin in PeruFigure 3 Buffer for Santa River Basin Figure 4 SRTM for Santa River BasinFigure 5 AGREE DEM for the Santa River BasinFigure 6 Flow Direction Grid for the Santa River BasinFigure7 Flow Accumulation Grid for Santa River BasinFigure 7.1 Detail of Flow Accumulation GridFigure 8 Stream definition Figure 9 Catchment Grid DelineationFigure 10 Catchment polygon processingFigure 11 Drainage Line ProcessingFigure 12 Drainage point processingFigure 13 Delineated Watershed for Santa River in PeruFigure 14 Delineated Sub Watersheds for Santa River Basin

34

Figure 15 Geo database for the Santa River BasinFigure 16 Contours for the Santa BasinFigure 17 Arc Hydro for the Santa River BasinFigure 18 Hydro Network Santa JunctionsFigure 19 Direction of Flow in the Santa River BasinFigure 20 Longest Flow Path in the Santa BasinFigure 21 Localization of stations of precipitationFigure 22 Mean Precipitation in stations of the Santa River BasinFigure 23 Variation of monthly precipitation in the Tablacacha subwatershed (Mountain from Peru)Figure 24 Variation of monthly precipitation in the Tablacacha Anta (Mountain from Peru)Figure 25 Variation of monthly precipitation in the Rinconada station (Coast from Peru)Figure 26 Annual Precipitation in the sub watersheds in the Santa River BasinFigure 27 Distribution of volume of precipitation in the Sub watershedsFigure 28 Monthly and annual mean discharge in the Condocerro Station. Santa River BasinFigure 29 Flow Duration curve in the Condocerro station in the Santa River Basin

35