Name________________________________________________Geology 724Spring 2001Quiz (50 points)Name________________________________________________1. Indicate whether the statement is true (T) or false (F). (15 points)a) In the Island Recharge Problem, the calibration is more sensitive to hydraulic conductivity (K) than to recharge (R). b) As a general rule there should be a minimum of five time steps in each stress period.c) Suppose we design a two-dimensional profile model of an unconfined aquifer using MODFLOW in “layer orientation” (i.e., using multiple rows and columns but only one layer).In this simulation, the value for the parameter “laycon” should be set to represent a confined aquifer.d) A steady state model solved using the LaPlace Equation with all specified head boundary conditions is insensitive to changes in hydraulic conductivity.e) Land surface elevation is never input to MODFLOW unless the ET (evapotranspiration) package is used.2. Briefly answer the following questions. (30 points)a) What is the purpose of a sensitivity analysis?b) Define sensitivity coefficient.c) Define conductance as a function of leakance.d) UCODE is a parameter estimation code that solves the inverse problem. Explain what this means as applied to groundwater flow modeling. That is, what does this code do when applied to a groundwater flow problem?e) Describe three ways in which a finite element model differs from a finite difference model.f) GFLOW is an analytic element code. Briefly explain how the AE method differs from themethod of finite differences.g) Describe how each of the following is used in a particle tracking code.1. Darcy’s law.2. Interpolation scheme 3. Tracking scheme (e.g., Runge Kutta method)h) Name three techniques that can be used to define the boundary conditions of a finite difference model when physical boundaries are located far from the area of interest. 3. Consider the 6 nodes shown below. Suppose these nodes are the 6 nodes in the upper left hand corner of a two-dimensional horizontal finite difference grid of a confined aquifer. The nodes in the top row are specified head cells and the nodes in the bottom row are active cells in a steady-state simulation. The numbers in each cell are the head values. Suppose we wishto switch from the specified head boundary conditions used in the steady-state model to specified flux boundary conditions in preparation for a transient simulation involving a pumping well located somewhere in the problem domain. Calculate the values of the volumetric flux (m3/day) that you would assign to boundary cell A. Be sure to indicate the sign of the flux, where (+) indicates inflow to the model and (–) indicates withdrawal of waterfrom the model. Assume that the aquifer is isotropic and transmissivity is 300 m2/day; the nodes are equally spaced such that x =y = 100 m. (5 points) Cell A12 9 8 11 10