# ComputeURF

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Computes the Unit Response Function for a given streamline.

Version : 1.0

Author : George Kourakos

email: giorgk@gmail.com

web : http://groundwater.ucdavis.edu/msim

Date 18-Dec_2012

Department of Land Air and Water

University of California Davis

## Contents

## Usage

URF=ComputeURF(XYZ, Vxyz, opt)

## Input:

* XYZ* : Streamline coordinates [Np x 3].

* Vxyz* : Velocity of streamline points.

* opt* : An option structure with the following fields:

dx : discretization along streamline

dt : time discretization in years

Ttime : Total simulation time

Lmin : Minimum length for numerical solution. For streamlines with length less than Lmin an analytical solution will be used.

lambda.type : 1->lambda is scalar : 0->variable

lambda.val : if type == 1, decay = lambda.val(1), if type == 0, decay = lambda.val ( lambda.val has to be equal to Np)

## Output data

* URF* : Unit response function

**Note**: The first point in XYZ is the starting point of the backward particle tracking near the CDS (e.g. the wells).

In FEM formulation we assume that the first point is near the land surface, therefore we reverse the order inside the script.

|---v1----|---v2---|----v3-----| ------------------------------------- x1 x2 x3 x4