CONTENTS 



Page 



CONVERSION FACTORS, U.S. CUSTOMARY TO METRIC (SI) 5 



I INTRODUCTION 7 



II LINEAR DAMPING STILLING WELLS 7 



III DESIGN OF THE WATER LEVEL RECORDER 15 



IV A SAMPLE DESIGN 16 



V CONCLUSION 18 



LITERATURE CITED 21 



FIGURES 



1 Approximate distribution of ocean surface wave energy illustrating 



the classification of surface waves 8 



2 The linear stilling well 9 



3 Response characteristics of a linear stilling well 12 



4 Theoretical linear stilling well design to obtain 90 percent of 



a 1-hour wave 13 



5 Theoretical linear stilling well design to dampen 95 percent of 



a 10-second wave 14 



6 Amplitude response of the Pentwater stilling well predicted 



from the drainage test 17 



7 Pentwater water levels, November 1974 19 



8 Spectra of water levels for Pentwater Lake, Michigan, for 



November 1974 20 



