MATHEMATICAL MODELLING FOR COASTAL ENGINEERING

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3 GOVERNMENT OF INDIA CENTRAL WATER AND POWER RESEARCH STATION KHADAKWASLA, PUNE MATHEMATICAL MODELLING FOR COASTAL ENGINEERING TECHNICAL REPORT No MAY 2013 HYDRODYNAMIC STUDIES TO ASSESS THE IMPACT OF THE PROPOSED DEVELOPMENT OF FLOATING STORAGE RE- GASIFICATION UNIT AT KAKINADA DEEP WATER PORT

4 Government of India Ministry of Water Resources CENTRAL WATER & POWER RESEARCH STATION Khadakwasla, Pune : , , , Fax: : kudale_md@cwprs.gov.in No.MMCE-I/2013 Dated: Director (Commercial) Andhra Pradesh Gas Distribution Corporation Ltd., Parisrama Bhavan, 2 nd Floor, /B, Fateh Maidan Road, Basheerbagh, Hyderabad Andhra Pradesh Sub: Hydrodynamic studies to assess the impact of development of Floating Storage Re-gasification Unit at Kakinada Deep Water Port. Sir, Enclosed please find six copies of Technical Report No titled Hydrodynamic studies to assess the impact of the proposed development of Floating Storage Re-gasification Unit at Kakinada Deep Water Port and 3 sets of soft copy (CD). The receipt of the same may please be acknowledged. Thanking you, Yours faithfully, Encl: Technical Report in duplicate (M. D. Kudale) Joint Director CC : Director for information CC : Shri MDK, JD /CRO (MMCE)/ SRO(MMCE)/ CRO (TC)/OC

5 A. REPORT DOCUMENTATION SHEET Technical Report No Date: MAY, 2013 Title : HYDRODYNAMIC STUDIES TO ASSESS THE IMPACT OF THE PROPOSED DEVELOPMENT OF FLOATING STORAGE RE-GASIFICATION UNIT AT KAKINADA DEEP WATER PORT Officers Responsible for Conducting the Studies: Smt. A. M. Vaidya, Chief Research Officer, Smt. S. Kulkarni, Senior Research Officers, Smt. V. Roy, Research Assistant under the overall supervision of Shri M. D. Kudale, Joint Director. Name and Address of Organization Conducting the Studies : Mathematical Modelling for Coastal Engineering Coastal and Offshore Engineering Laboratory Central Water and Power Research Station, Pune, India Name and Address of Authority Sponsoring the Studies: Director (Commercial) Andhra Pradesh Gas Distribution Corporation Ltd., Parisrama Bhavan, 2 nd Floor, /B, Fateh Maidan Road, Basheerbagh, Hyderabad Andhra Pradesh Synopsis : Andhra Pradesh Gas Distribution Corporation Limited (APGDC) is developing LNG Floating Storage and Regasification Unit (FSRU) Project at Kakinada Deep Water Port. The proposed facility comprises of Jetty, FSRU, Subsea pipeline, Onshore Receipt Facility and connectivity to the existing Gas grid. The facility is proposed to be developed on the leeside of the existing breakwater which will provide tranquil bay conditions for round the year operation of the facility. In order to examine the technical feasibility of the proposed FSRU based LNG Terminal, mathematical model studies for wave propagation were carried out to investigate the wave conditions along the approach channel and near the coastline adjacent to the project site and Uppada coastline. For simulation of wave propagation from offshore to nearshore region, mathematical model MIKE21-SW was used. The wave propagation studies showed that the predominant directions of wave approach are from East, ESE, SE, and SSE. No significant change in the wave climate in the vicinity of Port area was observed due to deepening and widening of the channel. The proposed development of FSRU project is within the KDWP Harbour (Protected) area at Kakinada and will not have any significant effect on the adjacent coastline at Uppada. The present erosion at Uppada coastline is mainly due to starvation of the beach and the severe wave attack during the monsoon. Keywords Breakwater, Wave Transformation, Wave height, Refraction, Shoaling etc. CWPRS Technical Report No.5075 May 2013

6 TABLE OF CONTENTS 1. INTRODUCTION 2. SCOPE OF STUDIES 3. SITE CONDITIONS 3.1 Tidal Levels 3.2 Wave Data In Deep Sea 4. WAVE PROPAGATION FROM DEEP WATER TO THE COAST 4.1 MIKE 21- SW Model 4.2 Wave Transformation Studies with MIKE21-SW 5. DISCUSSION ON RESULTS 6. SHORELINE CHANGES AT UPPADA 6.1 Longshore Sediment Transport at the coast 6.2 Effect of Widening and Deepening of the Channel on Uppada Coastline 7. CONCLUDING REMARKS CWPRS Technical Report No.5075 May 2013

7 HYDRODYNAMIC STUDIES TO ASSESS THE IMPACT OF THE PROPOSED DEVELOPMENT OF FLOATING STORAGE RE-GASIFICATION UNIT AT KAKINADA DEEP WATER PORT TECHNICAL REPORT No MAY INTRODUCTION Andhra Pradesh Gas Distribution Corporation Limited (APGDC), Hyderabad a joint venture of APGIC (wholly owned company of APIIC & APGENCO) and GAIL Gas Limited (a wholly owned subsidiary of GAIL (India) Limited) is developing LNG Floating Storage and Regasification Unit (FSRU) Project at Kakinada Deep Water Port. The proposed facility comprises of Jetty, FSRU, Subsea pipeline, Onshore Receipt Facility and connectivity to the existing Gas grid. The facility is proposed to be developed on the Leeside of the existing breakwater which will provide tranquil bay conditions for round the year operation of the facility. Kakinada Port is situated on the east coast of India at latitude N and longitude of E. It is situated 170km south of Visakhapatnam. The proposed development envisages regasification of LNG on the proposed Floating Storage and Regasification Unit (FSRU) berthed at the proposed island Jetty on the lee side of the existing breakwater. The FSRU will include facilities to import LNG from LNG carriers (LNGC), provide LNG storage and subsequent regasification to convert the LNG to natural gas to send out to the coast. The regasified natural gas will be sent by sub-sea pipeline to an on-shore receiving facility (ORF) at the land fall point. The proposed island jetty will be utilized to berth/ moor the FSRU as well as receive the LNG carriers consists of The layout of the proposed floating terminal is shown in Figure 1. The proposed development 1. A berthing and manoeuvring area to the west of the existing breakwater dredged to 14.5m depth with respect to CD 2. An island jetty to be constructed on the lee side of the existing breakwater. 3. An FSRU moored to the proposed island jetty on one side and LNGC moored on the other side. 4. High Pressure subsea pipeline to be laid from the jetty to proposed ORF. 5. The existing 160 m wide and 14m deep entry channel will be widened to 250 m and dredged to 14.5 m depth with respect to CD. Necessary dredging will be carried out to make 700 m turning circle and also to create berthing / mooring pockets for FSRU / LNGC to be berthed alongside proposed island jetty. CWPRS Technical Report No.5075, May

8 In order to examine the technical feasibility of the proposed FSRU based LNG Terminal, APGDC approached CW&PRS to conduct detailed hydrodynamic studies, as per point no (viii) and (x) of the Terms of Reference issued by MoEF vide their letter no 11-70/2012-IA-III, to investigate effect of proposed dredging, on leeside of breakwater and widening and deepening of the approach channel and turning circle on the surrounding wave hydrodynamics and its subsequent effect on the adjacent coastline near the project site including Uppada if any, in line with the MoEF OM dated Accordingly Mathematical model studies for wave propagation were carried out to investigate the wave conditions along the approach channel and near the coastline adjacent to the project site and Uppada in particular. The details of these studies are presented in this Report. 2. SCOPE OF STUDIES Analysis of UK Meteorological Office (UKMO) wave data to obtain offshore wave climate. Wave transformation studies to obtain wave heights and wave direction along the approach channel and surrounding area. Analysis of nearshore wave conditions after the proposed deepening and widening of the channel and to examine its effect on the shoreline at Uppada. 3. SITE CONDITIONS 3.1.Tide Tidal conditions at Kakinada are tabulated in Table 1 Table 1 : Tidal conditions at Kakinada Height (m) above Chart Datum (CD) Maximum high water spring 1.5m Maximum high water neap 1.1m Mean sea level 0.9m Minimum low water neap 0.6m Minimum low water level spring 0.2m CWPRS Technical Report No.5075, May

9 3.2. Wave Data in Deep Sea The offshore wave data from UK Meteorological Office (UKMO) off Kakinada for a period from 28 th May 1999 to 30 th June 2011 were available in CWPRS data bank. From the analysis of these data, frequency distribution of wave heights from different directions during different seasons and entire year for the above offshore data was obtained and is given in Tables-1 (A-D). The corresponding wave rose diagrams are presented in Figs. 2(A-D). TABLE 1 A PERCENTAGE OCCURRENCE OF WAVE HEIGHT & WAVE DIRECTION OFF KAKINADA FOR SOUTH-WEST MONSOON PERIOD (JUN-SEP) WAVE HT(m) TOTAL DIRECTION TOTAL CWPRS Technical Report No.5075, May

10 TABLE 1 B PERCENTAGE OCCURRENCE OF WAVE HEIGHT & WAVE DIRECTION OFF KAKINADA FOR NORTH-EAST MONSOON PERIOD (OCT-JAN) WAVE HT(m) TOTAL DIRECTION TOTAL TABLE 1 C PERCENTAGE OCCURRENCE OF WAVE HEIGHT & WAVE DIRECTION OFF KAKINADA FOR NON-MONSOON PERIOD (FEB-MAY) WAVE HT(m) TOTAL DIRECTION TOTAL CWPRS Technical Report No.5075, May

11 TABLE 1 D PERCENTAGE OCCURRENCE OF WAVE HEIGHT & WAVE DIRECTION OFF KAKINADA FOR ENTIRE PERIOD (JAN-DEC) WAVE HT(m) TOTAL DIRECTION TOTAL From Table 1(A) and Fig.2(A) it could be seen that during south-west monsoon, the waves approach predominantly from South,SSW, SW and WSW directions with 56%, 14%, 16% and 8% occurrence respectively with the maximum wave heights of the order of 4.5 m. During northeast monsoon period (Table 1(B) and Fig. 2(B)) waves approach predominantly from SSE and South directions with 9% and 63% occurrence respectively. In the non-monsoon period (Table1(C) and Fig.2(C)) the predominant directions of waves are from SSE, South and SSW directions with 14%, 72% and 11% occurrence respectively and the wave heights are up to 3.5 m. The wave climate during the entire year (Table 1(D) and Fig. 2(D)) indicates that the predominant wave directions in deep water are from SSE, South, SSW and SW directions with 9%, 64%, 9% and 6% occurrence respectively with the maximum wave heights of the order of 4.5m. However, its percentage of occurrence is very small. These deep water wave data were transformed using a spectral wave model to get the nearshore wave climate in the vicinity of the proposed port expansion at Kakinada. CWPRS Technical Report No.5075, May

12 4.0 WAVE PROPAGATION FROM DEEP WATER TO THE COAST 4.1 MIKE-21 SW Model For simultion of wave propagation from offshore to nearshore region, mathematical model MIKE21-SW was used. Brief description of the model is given below As waves travel from deep sea to shallow coastal waters, they undergo changes in direction and height due to the processes of refraction and shoaling. The simulation of wave transformation from deep to shallow waters was carried out using MIKE 21 SW model. MIKE 21 SW model is a spectral wind wave model based on unstructured mesh. The model simulates the growth, decay and transformation of wind generated waves and swell in offshore and coastal areas. The governing equation is the wave action balance equation. In horizontal Cartesian coordinates the conservation equation for wave action is N.( N ) t S where N( x,,,t) is the action density, t is the time, x = (x,y) is the Cartesian coordinates, = ( C x, C y, C σ, C θ ) is the propagation velocity of a wave group in the four dimensional phase space x, and. S is the source term for the energy balance equation. is the four dimensional differential operator in the x, and space. The equation is solved using cell centered finite volume method. 4.2 Wave Transformation Studies with MIKE21-SW Bathymetry in the offshore region of Hope Island is fairly simple, consists of almost parallel contours from 10m depth upto 200m depth. The bathymetry data in the offshore were taken from CMAP data base and bathymetry in the port area was taken from Hydrographic chart No supplied by Project. An area of 72km by 35 km with an unstructured mesh was considered for studies with MIKE 21 SW model which extends up to 100 m in deep sea and high water line near the shore. The model was run for incident waves from NE, ENE, East, ESE, SE, SSE and South which are the predominant wave directions in deep sea (Table 1D) with incident wave height of 4m. The model was run for the highest high water level at 1.5m for following conditions: CWPRS Technical Report No.5075, May

13 1. Preexisting condition Without any channel and breakwater (Fig. 3 ) 2. Existing condition - Offshore breakwater of length 1050m and an approach channel dredged to depth varying between 12.5m and 14.5m with width 160m (Fig. 4 ) 3. Proposed FSRU development Dredging in the proposed turning cirle of 700 m diameter and berthing pockets to 14.5m depth and deepening of approach channel to 14.5m depth and widening to 250m. (Fig. 5 ) Plots of wave height contours and wave vectors in the model area and near the Uppada coast are shown in Figs. 6 to 8 for the predominant incident wave direction South, for the preexisting, existing and proposed channel conditions respectively. Wave heights were extracted from the model results for all the incident wave directions along the channel and Uppada coast at regular distance as shown in Fig.9. Fig. 10A, 10B and Fig 11 show comparison of wave heights along the channel and along the coast at Uppada for the three conditions. Wave heights and wave directions in 7m depth near the Uppada coast were extracted from the model results for all the incident wave directions. This information of wave height and direction in 7m depth was applied to yearly offshore wave climate (Table 1D) to obtain frequency distribution of wave height and wave direction near the Uppada coast. Table 2 shows frequency distribution of wave heights from different directions during entire year in 7m depth near the Uppada coast for the proposed channel conditions. Fig.12(A&B) show nearshore wave rose diagrams in 7m depth near the Uppada coast for the existing and proposed channel conditions. TABLE 2 PERCENTAGE OCCURRENCE OF WAVE HEIGHT & WAVE DIRECTION AT KAKINADA IN 7 m DEPTH FOR ENTIRE PERIOD(JAN-DEC) (UKMO DATA) WAVE HT(m) TOTAL DIRECTION CALM % TOTAL Significant wave heights observed near the landfall point in 3m depth are given in Table 3. CWPRS Technical Report No.5075, May

14 TABLE 3 MAXIMUM SIGNIFICANT WAVE HEIGHTS NEAR THE LANDFALL POINT Incident Wave Direction /Incident Wave Height Mean Wave Direction 45 0 N /4m 0.8m 87 0 N N /4m 1.4m 90 0 N 90 0 N /4m 1.5m 93 0 N N /4m 1.3m 97 0 N N /4m 0.9m N N /4m 0.5m N N /4m 0.3m N N /4m 0.1m N 5.0 DISCUSSION ON RESULTS Wave propagation studies carried out for transformation of deep water wave conditions to nearshore showed that the directions of wave approach are from East, ESE, SE, and SSE. The annual frequency distribution of waves shown in Table 2 indicate that waves approach predominantly from East, ESE, SE, and SSE directions with percentages 2%, 7%, 74% and 9% respectively. From Figs. 10 and 11, it is seen that there is marginal change in wave heights along the channel as well as near the Uppada coast due to proposed deepening and widening of the channel and dredging of port area in the lee side of the breakwater. It is seen that the wave heights along the coast are seen to reduce or increase by 0.1m to 0.2m with the proposed dredging conditions. The Uppada coast is at a distance of about 10km from the proposed site of development. There is no significant change in the wave heights, frequency distribution of wave height and wave direction (Ref: Fig.12) near the Uppada coast due to deepening and widening of the channel. 5.0 SHORELINE CHANGES AT UPPADA The coastline at Uppada is in the shadow zone of the Hope Island. Therefore wave climate and littoral drift trend is different from the normal trend existing at other locations on the east coast of India. CWPRS Technical Report No.5075, May

15 5.1 Longshore Sediment Transport at the coast Waves breaking obliquely to the coast and the longshore currents they generate cause the longshore movement of sediments which may flow along an extended length of beach. Sometimes this transport results in a local rearrangement of sand into bars and troughs. At other times there are extensive longshore displacements of sediments i.e. littoral drift, moving thousands of cubic meters of sand along the coast each year. The coastline at Uppada is subjected to severe erosion due to high wave action during monsoon. Due to the sandspit, the sediment transport across the bay is cut off, as the sediment transport is utilized for growth of the sandspit. This growth of sandspit as well bypassing of the sediments towards the northern coastline prevents replenishment of the Uppada coastline. The erosion of the coastline is mainly due to starvation of the beach and the severe wave attack during the monsoon. 6.2 Effect of Widening and Deepening of the Channel on Uppada Coastline Changes in the shoreline are mainly due to movement of the sediments in the surf zone, caused by currents generated by the breaking of obliquely incident wind waves. From the results of mathematical model studies of wave transformation, it is seen that there is no significant change in wave conditions near the coast due to deepening and widening of the channel (Fig.10 & Fig.11). Therefore the proposed development of FSRU at Kakinada will not have any significant effect on the adjacent coastline. The erosion of the coastline is mainly due to starvation of the beach and the severe wave attack during the monsoon. 7. CONCLUDING REMARKS Mathematical model studies for wave propagation and probable shoreline changes at Uppada for the proposed development of FSRU at Kakinada Port were carried out at CW&PRS. Following are the main conclusions: Wave propagation studies carried out for transformation of deep water wave conditions to nearshore showed that the directions of wave approach are from East, ESE, SE, and SSE. with percentages 2%, 7%, 74% and 9% respectively. There is no significant change in the wave climate in the vicinity of Port area due to deepening and widening of the channel. The proposed development of FSRU project is within the KDWP Harbour (Protected) area at Kakinada and will not have any significant effect on the adjacent coastline at Uppada. The present erosion at Uppada coastline is mainly due to starvation of the beach and the severe wave attack during the monsoon. CWPRS Technical Report No.5075, May

16 EXISTING BREAKWATER Fig. 1 : PROPOSED FSRU DEVELOPMENT AT KAKINADA

17 A. South West Monsoon (June-September) B. North East Monsoon (October- January) C. Non Monsoon Period (February- May) D. Entire Year (January-December) Fig 2(A-D): OFFSHORE WAVE ROSE DIAGRAMS

18 Uppada Fig 3. : BATHYMETRY FOR WAVE PROPAGATION STUDIES (PRE-EXISTING CONDITION)

19 Uppada Breakwater Channel Fig 4. : BATHYMETRY PLOT FOR WAVE PROPAGATION STUDIES (EXISTING CONDITION)

20 Uppada Approach Channel Breakwater Proposed Dredging Fig 5. : BATHYMETRY PLOT FOR WAVE PROPAGATION STUDIES (PROPOSED FSRU DEVELOPMENT)

21 Uppada FIG 6.: WAVE HEIGHT DISTRIBUTION FOR PRE-EXISTING CONDITION FOR WAVES INCIDENT FROM SOUTH DIRECTION ( INCIDENT WAVE HEIGHT : 4.0 m)

22 Uppada FIG.7: WAVE HEIGHT DISTRIBUTION FOR EXISTING CONDITION FOR WAVES INCIDENT FROM SOUTH DIRECTION ( INCIDENT WAVE HEIGHT : 4.0 m)

23 Uppada FIG 8.: WAVE HEIGHT DISTRIBUTION FOR PROPOSED LAYOUT FOR WAVES INCIDENT FROM SOUTH DIRECTION ( INCIDENT WAVE HEIGHT : 4.0 m)

24 Landfall Point Dredging for turning circle and berthing pockets Fig.9: LOCATIONS OF OBSERVATION POINTS ALONG THE CHANNEL AND UPPADA COAST

25 Pre existing 2 Pre existing 0.6 Existing 1.5 Existing 0.4 Proposed 1 Proposed INCIDENT WAVE DIRECTION:45 INCIDENT WAVE DIRECTION: Pre existing 2 Pre existing 1 Existing Proposed Existing Proposed INCIDENT WAVE DIRECTION:67.5 INCIDENT WAVE DIRECTION:112.5 Fig.10A : WAVE HEIGHT DISTRIBUTION ALONG CHANNEL FOR DIFFERENT INCIDENT WAVE DIRECTIONS

26 Pre existing Existing 0.6 Proposed0.4 Pre-existing Existing Proposed INCIDENT WAVE DIRECTION: INCIDENT WAVE DIRECTION: Pre existing 0.4 Pre-existing 1 Existing Proposed Existing Proposed INCIDENT WAVE DIRECTION:157.5 INCIDENT WAVE DIRECTION:202.5 Fig.10B : WAVE HEIGHT DISTRIBUTION ALONG CHANNEL FOR DIFFERENT INCIDENT WAVE DIRECTIONS PDF compression, OCR, web optimization using a watermarked evaluation copy of CVISION PDFCompressor

27 Pre existing Pre existing 1.5 Pre-existing Existing 0.4 Existing 1 Existing 0.5 Proposed 0.2 Proposed 0.5 Proposed INCIDENT WAVE DIRECTION:180 INCIDENT WAVE DIRECTION:45 INCIDENT WAVE DIRECTION: Pre-existing Pre existing 1 Pre existing 0.3 Existing Existing 1.5 Existing 0.2 Proposed 0.5 Proposed 1 Proposed INCIDENT WAVE DIRECTION:67.5 INCIDENT WAVE DIRECTION:135 INCIDENT WAVE DIRECTION: Pre existing 1.5 Pre existing 1 Existing 1 Existing 0.5 Proposed 0.5 Proposed INCIDENT WAVE DIRECTION:157.5 INCIDENT WAVE DIRECTION:90 Fig.11: WAVE HEIGHT DISTRIBUTION NEAR UPPADA COAST

28 (A) EXISTING CONDITION (B) PROPOSED FSRU DEVELOPMENT Fig. 12 ROSE DIAGRAMS AT UPPADA IN 7M DEPTH (JANUARY-DECEMBER)

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