Sand harvesting from coral reef slopes 2016-2019


Sand harvesting from the 30-50 m reef slopes on the south coast of Kenya – at Waa and Tiwi – has become a focus for conflict. The quality of sand deposits, width of the shelf and limited depth seem to make this one of the main options to fill the needs for construction in Mombasa’s Port – whether for railways, terminals and other facilities.

However, the coral reef is one of Kenya’s principal natural assets supporting the coastal economy and Counties, particularly for fisheries, tourism and coastal protection. The conflicts over sand harvesting here are a signature case study of the need for Marine Spatial Planning and integrated planning among different government sectors – and necessary if Kenya is to achieve its Blue Economy aspirations.

Sand harvesting on the outer reef slope of Kenya’s coast is apparently ramping up in recent years, due to demand for large scale construction projects for the material. However there is apparently no coordinated action to identify potential sources of sand/aggregate for construction, nor the pros and cons of different locations, minimizing environmental impacts and maintaining natural and other assets needed in other sectors such as fisheries and tourism.

Three ‘flashpoints’ have come up in the last 4 years, outlined in the tabs below, and see the fourth tab for more information about sand harvesting and its impacts.

Container Terminal, 2019Mtwapa, February 2016Standard Gauge Railway, 2015-16More about Sand harvesting

Two simultaneous activities are being carried out and are very different, but being confused in the press (see links below):

1) Sand harvesting

This is being done by the vessel Wilhelm van Oranje, a Dutch ship, apparently contracted to the engineering firm Boskalis on contract to a Japanese principal contractor working on the Phase 2 Container terminal. By its tracks (at left) it is clearly dredging the ship channel in Port Reitz, going out and dumping this collected spoil at the designated site offshore, then turning south and collecting sand from off the Waa and the Tiwi reefs for construction of the terminal.

The government has not formally designated locations for sand harvesting from the sea, see the tab on early conflicts on the same issue in 2015-16. Each project that causes some environmental alteration certainly needs an EIA under the Environmental Management and Coordination Act (EMCA). The EIA (2007) and addenda (2012, 2013) that are being presented for allowing this activity are outdated, and environmental monitoring is poorly designed to manage the sand harvesting activities in real time.

As in 2015-16, the vessel is going to collect sand from the nearest location possible – the Waa-Tiwi-Diani reef – without any consideration of environmental impacts.

 

2) Dredging in the port

This is being done by two vessels – the Willem van Oranje and the Jun Hai 6, one for the Kenya Oil Terminal, and the other for the Phase 2 Container Terminal. The collected material (or ‘dredge spoil’) has to be dumped at sea and it is standard for all major ports globally to have a designated dumping site offshore. There is a spot on old marine charts for Mombasa, as shown by vessel tracking software, about 4 km out from the end of the channel.

If this is within legal distance limits for dumping is not at present clear.

 

Articles in the press on this issue:

The Conversation Africa, 22 March 2019

The Sunday Nation, 19 March 2019

The Star, 16 March 2019

From 3-10 February two separate vessels were sighted off Mtwapa Creek and the Mombasa Marine Park and Reserve, apparently conducting sampling of the sea bottom off the reef. The operations appear similar to those that have been stopped off the south coast (see adjacent tab), fuelling speculation that since that activity has been stopped, this location may be being considered as an alternative.

However, no consultation has apparently been undertaken, putting this activity in the same category as the south coast operations, and liable to also be stopped through action in the National Environment Tribunal

3 February 2016 - standard freighter with crane

3 February 2016 – standard freighter with crane

10 February 2016 - Dredger

10 February 2016 – Dredger

23 January 2016. Sand harvesting on the outer reef slope from Likoni to Tiwi (part of the south coast of Kenya, south of Mombasa), by the China Road and Bridge Corporation, for construction of Kenya’s new Standard Gauge Railway has been stopped by Kenya’s National Environment Tribunal. This decision was reached by the Tribunal on a case brought by the South Coast Residents Association, opposing the decision by Kenya’s National Environment Management Authority (NEMA) to allow harvesting on the basis of a preliminary ‘Environmental Report’ brought by the CRBC. Instead, the NET required that a full Environmental Impact Assessment must be conducted before NEMA can grant approval.

Lead+Consultant+and+representatives+of+key+government+organizations+on+site+visit+to+proposed+sea+sand+harvesting+siteThe initial “EIA” submitted by the CRBC contained almost no relevant information on coral reef and seagrass habitats, sediment resuspension by dredging, and sediment plume movements driven by wind, currents and waves. The EIA team did not conduct an environmental or biological assessment, did not survey the reef, marine habitats, or sand resource being harvested, and did not even get on a boat (see image at right) – the closest they got to the site was the beach (see image from the “EIA report”).

This created significant controversy, as documented in the following links.

The Star, 19 February 2016

Business Daily, 7 July 2015

Blog links 1 and 2

The window below contains the EIA, the license approval from NEMA, comments submitted on it to NEMA by CORDIO and other documents.

Sand harvesting acts through a mix of pressure and suction – to loosen the sand at the surface, then suck it up into the vessel. There is also then an overflow of the water while the desired sand settles within the ship. Of course, the overflow water carries a very high load of the fine sediments suspended in the water (and which anyway are likely not desired for construction, so its possible the machinery intentionally keeps all the fine sediments resuspended to NOT let them be retained in the ship, and get discharged back into the sea. So very extensive sediment plumes may be kicked up both on the bottom, and at the surface.

While the desired sand is not directly ON a coral reef – in the area in question I think there is a shelf slope at about 30-50 m deep that has sand of the right characteristics, and the sand layer itself is thick enough to make dredging/harvesting work. But both bottom and surface plumes are extremely thick and far beyond natural sediment loads for sandy-bottom and coral reef/seagrass communities, and currents/tides/winds may push them quickly into shallower water where the highly vulnerable coral reefs and seagrasses are.

The plumes cut down light, reducing photosynthesis and settling sediments can stress species on the bottom, suffocate them, and potentially cover them completely – causing death.

The video and images below show the intensity of the surface plume set out by sand harvesting.