Dredge-spoil dumping in Mombasa

The issue of dredge spoil dumping is a charged one in Mombasa, with a history of poor information and knowledge of what is happening, what is legal and environmental regulations controlling it.

This brief is written to try to help identify the key issues about current dumping practices in Mombasa, and what, if anything, needs to be changed and how.


  • Background – dredging and dumping

Dredging to deepen ports is a necessary activity in port/terminal construction and for regular maintenance due to in-filling of channels. A result of dredging (picking up bottom sediments into the ship) is that this material (called dredge ‘spoil’) must be dumped at sea.

Dumping involves unavoidable damage to the seafloor and communities that the dredge spoil settles on. It is also unavoidable that dropping the sediment causes a plume of fine sediment in the water column, which flows with the currents. The deeper the water where this is done, the more the sediment disperses so reducing the intensity of impact and spreading it over a wider area of bottom and volume of seawater.

All major ports require dredging to maintain and deepen channels, so a compromise must always be found that enables dredging and dumping, and reduces impacts to acceptable levels.


  • Where dumping has occurred in Mombasa

Since pre-independence, dumping of dredge spoil was done at a location marked on Admiralty Charts, that also allowed for dumping of explosives. Its location was xxx km from the channel entrance (finding the location now).

In 2011, following controversies around dumping practices, the multi-agency meeting on 11 July 2013, referred to in the KPA public notice (of 30 March 2019), identified a new dumping location – the yellow box in the map.

The bases of this decision were:

>> a modelling study, which determined that because of the prevailing currents, the silt from dumping that is carried in the water is pushed northwards parallel to the shore, and not into the shore.

>>for the type of mud that is collected in Port Reitz, a horizontal distance of 3 km was identified as sufficient to reduce silt concentrations to have no impact.

>> the boundary of the Mombasa Marine Reserve, and the coral reefs off Shelly Beach were used as the baseline, so a location 3 km from each of these was identified.

Map – The harbour entrance to Mombasa showing the shipping channel, Mombasa Marine Reserve and Park (blue boxes) and coral reefs. The main currents are shown, flowing northwards offshore, and tidal flow in and out of the channel. The current dredge spoil dumping site is shown by the yellow box, using the coordinates published by KPA in the notice on 30 March 2019.

As per the decisions at that time this is the legal dumping site for dredge spoil, and the current activities (assuming they are dumping within this box!), as well as past/future ones are operating as per legal environmental guidelines. If stakeholders DON’T like what is happening (e.g. if operators are dumping outside of this location, or they are, but impacts are being documented), there are due processes through NEMA to push for assessment and review (but see last section).


  • Does dumping have an impact?

What is not so clear is the veracity of the findings from the modelling study mentioned above, and results from environmental monitoring to date. The public notice indicates that monitoring and assessment have shown no significant impact, but this information is not available to the public. A key role that the authorities should play (in this case KPA, KMA, NEMA) should be to provide adequate public communications, which means publishing public reports backed up by data and good analysis, to demonstrate their claims that impacts are minimal.


  • Where are we now?

A massive public outcry in the last two weeks resulted in stoppage of the ongoing dredging/dumping activities and a stakeholder meeting bringing together the authorities (KPA, KMA, NEMA), the project contractors (for the Kenya Oil Terminal and Phase II Container Terminal), and stakeholders from tourism and research. The cause of the outcry was a failure in confidence that dumping was being regulated AND that it is having no impact as claimed by the authorities.

As a result of the meeting, my impression of the agreement was that the following steps would be undertaken:

1) – an immediate clarification is needed for the public about a) the legal status and location of the dumping site, and b) assurance that all dumping is being done within the designated location. The public notice (30 March 2019) provides the first part of this, the second part is to demonstrate that all dumping is complying with this location, and this needs to be done still.

2) – the impact of dumping needs to be demonstrated credibly and scientifically, and this needs to be done within a short timeframe. For this, all monitoring data since the site designation in 2011 needs to be analyzed and reported in an open format. A technical report, inviting review from the scientific community would be the most desirable way to build confidence in the findings, and KPA and contractors should commit to acting on the findings.

3) – IF it is found from the above that impacts are not acceptable to some stakeholders, then a process to determine relevant mitigation, such as by designating a site farther offshore will be necessary. Again, a specific time frame for starting and ending this process needs to be identified.

4) – current EIAs in relation to dumping are out of date (e.g. for the Phase II Container Terminal, the main EIA was done in 2007, and updates to it in 2012 and 2013), if not technically/legally, certainly in terms of stakeholder confidence. Those aspects related to dumping should be reviewed immediately, with consultative stakeholder processes that can help to inform actions under 2 and 3 above.


My own take …

… on criteria for acceptability of spoil dumping includes three aspects that need to be considered:

>> What is the impact to the seafloor life (and water column) and over what area? How about to adjacent coral reefs and seagrasses? Is it significant, and if so, is this an acceptable sacrifice?

>> In what direction, and how much, does the dredge spoil spread in the currents? Does it mainly flow northwards as predicted by the modelling study, or does a significant portion come close to the coral reefs, seagrasses and shoreline?

>> Standards to improve monitoring to ensure that any potential impacts are quantified reliably need to be identified. These standards should be incorporated into all existing and new Environmental Monitoring and Management Plans, and future EIAs.

This process may confirm or call in question the findings of the 2011 multi-agency meeting and identification of the current dumping site. If the latter is the case, a new location for dredge spoil dumping needs to be identified.


In conclusion …

My position is to call on KPA and the authorities to ensure they build on the first steps in stakeholder confidence building started with the stoppage of dredging/dumping activities and stakeholder meeting on 27 March 2019, the public notice on 30 March (ie. step 1a above) and continue with all the rest of the four steps. If done correctly, then in 2-3 years Mombasa could have a dumping policy and practices accepted by all parties, and that ensures smooth implementation of development plans without significant environmental and social impacts.

For stakeholders, it is essential to focus on factual/demonstrable impacts, and identify steps in a process. If things are not known, then they need to be identified and quantified – and in some cases the onus is on stakeholders to do this initially, in order to hold the authorities accountable and go the next step.