ES2102 2022 Mid Semester Hydrology and Geodynamics PDF

Indian Institute of science Education and Research Kolkata Department of Earth Sciences Hydrology and Geodynamics Subject No: ES2l02 Total Marks: 30 Time: l:30 hr...

Indian Institute of science Education and Research Kolkata Department of Earth Sciences Hydrology and Geodynamics Subject No: ES2l02 Total Marks: 30 Time: l:30 hr Exam: Mid Semester Autumn2022 lnstruction: Answer all questions 1. Prove that dh/ax2 + azh/ayz + dh/az2= (s/\ ah/a; where h=hydraulic head, s=storativity, T=transmissivity of a confined, homogeneous and isotropic aquifer. (g) 2. Show how to determine the Hydraulic conductivity of unconfined aquifer if the flow is radial and in steady state. (5) 3. What is residual drawdown? Explain with diagram why the drawdown curve differs from residual ( drawdown curve when data are plotted in a "Depth to water below original non pumping water level versus time". (1+3) 4. In the figure, the drawdown in confined aquifer is plotted as a function of time on semi- logarithmic paper. Why the plot is a straight line? What is the significance of to? (3+4) Drawdown (s') Time (t) Fig. 1 5. Calculate the drawdown in an observation well which is 400 m away from the pumping well if the discharge rate is 500 m3/day and the experimental well was pumped for 90 minutes. The transmissivity and storativity of the aquifer is 500 m'1day and 0.0005 respectively. Also calculate the pumping rate required to provide a drawdown of 2 m at that well after 300 minutes. Assume aquifer is confined and flow is transient. Please take the value of w(u) from the table pasted in the next page. (3+3) P.T.O.  t.{} :,{r "1 {} J.{i :U ri (f I Il il,r r 9,{}.:1. t {tll.i r1.l}"19 t3 {f.ilil31+ (),{t6l I {}.tlfif.ifr t!.{r{x}il r}.{10{l(}3s (l"tl {}.t)fl(x,l: 5tllt 1.8: 1,33 tl,Sl {l,T{t tl,s$ t'tJs {},.$ 0,ll 0":s.., ii| :.i,rH.1."ii l.r}{l 1.6lt LJ7 :.10 l. !5 1.01 I lr: ' l(t' tl,.l.l 5,f$ 5,:.1 1,9S.l,TI 1,51 {,11t {,?rr {,t{ ,l0.r x.6.i ?.r!{ ?.J3 ?.:J ?.t,1 (t-li-l {r.fitt {r.il 6.14 \; l{f * rr.9{ lt},lj f ,li4 q"st q.33 q. t{ ri,{r! x.fi(! r{,'id :': [{ I n' 1.1.*.{ :.:I I r:.r.1 | Lxi l l.tr.i l l..l5 l l.:$ | l.lh i |.rit I l(l'r I J.-5.r t.t,$s rJ..r4 r1.r5 l"1.i.rl t].?-5 l"l,{il} 13.'$fi I t,.t1 r[{1" t7.ttJ ll. t5 t6.i"r l6,J$ h.::1 l$,r)5 i,rl{l 15.?fi l5.tri o I I ', l(, " :$" ll ItJ.,l5 Irt.rtS llri,?tr t;{.5{ }ri.}s s.:ti I ?i.{}? I l?^-q"t i: lll lI :1.15 I1.7(r : t.l5 I l.{16 la],t{ i{}"h{} Itl.5{r :{).ll l{1,3.{ r". lil rl t4.?s l.{.rxr 1i.$5 :.1.-r{r It.l{ ::.{h l:.t{ | t:,b? 11.35.,. tll r: :1.{t5 Jh,.{ft 15.'ttt 15,ft1 It.1{ 15,36 :5, t t l.l.e? lJ.fib 3:lt| ll lh :ir ll(.wr l$.1{r ll,1}? l?.li Ji.rtr :i.{ I :?.:x ll.ltr ;+ l0 l{.11,{*r.1{}.u? l{1,56 3t},:7 l.l.ri: :u,$? :{ ?l :9.5tr 2rt.'lrr i'. I{tti ji,.l6 3-1.1?.1:.ti6 3l..1li 11,15.1':.ll 3'1,{}l J I.}ili.1L7fi o