Mark Gibson, Teagasc ConnectEd was joined by Owen Fenton and Daire OHuallichain, Teagasc, to discuss The Water Cycle – where does all the water go? and sediment impact on water quality.
The presentations were followed by a Questions and Answers session with the panel.
For more shows and information on the series and to register for future webinars visit:
https://www.teagasc.ie/corporate-events/sustainable-agriculture-webinars/
Hello my name is Mark Gibson and you’re listening to the podcast version of the Chagas signpost series a weekly webinar that promotes and examines sustainability in Irish farming I’m joined by this morning by Professor on Fenton and Dr Dara gulon research scientists based in jagas and mo Park
Gentlemen uh you’re very welcome to to our webinar this morning and Pat Uh Murphy you’re joining us from uh Wexford Pat you’re going to help us uh with the questions later on Pat Murphy is head of our chisk environment knowledge transfer program Owen and Dara maybe ow starting
With you could you maybe just introduce uh the work that you do in Chagas and um and we we’ll be talking more in depth then in relation to the the the water side of thing but maybe you could give us an indication of the type of research
Work that you’re you’re engaged in yeah no problem Mark um hello everyone I suppose my background really is in soil science water science soil hydrology especially but my background is very varied um I would have studied earth science and then geology so all rocks and then I would have studied
Hydrogeology so looking at water in the rocks and then I suppose now I’m more concentrated on the whole Continuum soil and subsoil and bedrock and how water travels around that landscape on the surface but also subsurface so soil water nutrients um a bit of everything very good very good and Dara you’re
You’re um you you cover the ecological side of things but also looking at the the sediment uh part of the the water cycle as well perhaps you could give us a an overview of some of the work that you’re you’re engaged in as well okay thanks Mark yes I’m a researcher with
Chaga space down in Johnson Castle but split between Johnson and mor Park and my workload is split into as well like so it’s covering Farmland biodiversity which is receiving a lot of attention in recent years which is great to see but then it’s also looking at the wider biodiversity and water quality in
Particular and looking at the ecology in what in streams and in open water and looking at the impact of sediment in particular in relation to how sediment can impact on that on these habitats on these freshwater habitats and result in declining water quality great So today
We’re going to be focusing on the the water cycle and getting a better understanding of those interactions within the landscape and on I think you’re you’re going to kick us off with h an overview and some I’ve seen your presentation some excellent Graphics there to to get that better
Understanding of of that interaction of of soil uh with the lands or water with the landscape so I want if you could share your your screen with us and uh you’re going to give us about a 15minute presentation and then Dara is going to present after you then and so I I
Encourage uh anybody who has questions throughout the presentation do send them through to us using the Q&A tab at the bottom of your screen and uh we’ll allow about 15 or 20 minutes for questions and answers at the end so on hand over to you and uh we will talk to you after
Your presentation okay thanks very much Mark so I suppose the title of my talk is the water cycle where does all the water go but equally this could be called where do all the nutrients go so what I’d like to convey today is if we know where the water is going in the
Landscape we will also know where the nutrients are going so this is the water cycle everyone kind of recognizes this from our geography textbooks um it’s a cycle it’s a continuous cycle it’s been around for a very very long time and it’s a series of flows and temporary
Stores so let’s look at precipitation precipitation as we usually think of it in Ireland is rainfall but remember precipitation could be sof liquid or a gas and that falls to the ground surface it’s intercepted by plants or trees and then it becomes infiltration or runoff infiltration starts into the soil and
Then it can’t go anymore saturation occurs and runoff of water occurs across the surface and that interacts with surface water then you get go back to your soil you get percolation of this water deeper down and that eventually becomes recharged to groundwater so we have a soil a subsoil and we also have
Bedrock underneath and that is also I suppose separated into two parts an unsaturated zone which isn’t full of water and a saturated part underground which is fully saturated and a division line between those I call it the water table now important to note here is that surface water and groundwater interact
Together they’re not separate and indeed groundwater and sea waterer interact together as well then look at evaporation water goes off to surface of of these water bodies condenses we all know about condensation on Windows it gets heavy and it falls again as precipitation now let’s zoom into a
Landscape more at Farm level you can see the river here going through a lovely landscape and you can see all these lines and arrows here on it what I’m just saying here is that water falls infiltration occurs but it also travels over the land and it travels along
Roadways on our Farms which it travels in our open ditches on farms in our drainage systems and it also ponds on the surface here a few examples of for example down here there’s a spring developing the spring and then connects with surface water in cars Landscapes we
Have sink holes and sinking streams and that’s all connecting to underground importantly here as well you can see that groundwater feeds surface water have you ever taught it’s not raining today but the river is is still flowing that’s because particularly in summer um the river is being fed by
Groundwater now let’s zoom in again and look at a a particular example on our landscape Springs what are Springs there’s a lot of mystery around Springs here you can see on a hill slope there’s infiltration of of rainwater into the soil into a permeable soil but underneath that soil it’s very very slow
It’s impermeable so a tank of water starts to build up in the soil and then that tank of water can’t go anywhere so it must move laterally and it pinches out along a hill slope as Springs above you get drier ice B soils and below this you get wetter soils now Springs
Disappear sometimes why is that in a drought the storage tank starts to recede down and the spring turns itself off then in a wet period again the storage tank builds up in the soil and the Springs appear again Springs are often drained off into open channels and
In cars Landscapes like this you get sink holes and sinking streams and I think of an agricultural system on top of a vulnerable landscape like this you’ll often have surface water disappearing underground going through C Limestone and then reappearing as Springs so therefore you must be cognizant that there’s a connection
Between the Surface subsurface and surface water we had a nitrate sensor in a spring which looked at flow we also measured rainfall and we also measured nitrate concentrations um you could see here as rainfall increases the flow or discharge in that spring increases and the nitrate concentration went up as well really
What I want you to look at here is in both those graphs the shape is quite similar so what we do at the surface influences nitrogen underground now let’s look at rainfall we live in North Atlantic Europe and we certainly live on an island which we forget sometimes and
We have a lot of rainfall if you draw a line between Belfast and Kerry west of that that line we get a lot more rainfall up to about three meters and east of that over in the sunny Southeast as I call it we only get one meter of
Rainfall every year but look at this graph it’s a u shape I want you to to look at we get rainfall in all of the months of the year but in particular around the shoulders of the year January February and then later September October November we get most of our
Rainfall but increasingly over time this U shape is becoming shallower and that’s because we’re getting more rainfall in our summer months so episodic rainfall events in summer is very very interesting and important in terms of runoff and especially runoff on roadways which I’ll get to later on so now look
At the soil the soil really controls infiltration or the movement of water across the soil the soil of course is made up of different components organic matter and here in its simplest terms gravel Stones sand silt and pl and in this experiment if you fill the same Container full of these materials and
Continuously poured water into how long would it take water to go through that gravel two minutes and look right over to your right it would take 200 years for that same water to go through clay so now let’s mix them all together into a soil profile and you come up with two
Extremes you come up with there on the left well- drained soil lovely brown colors it allows most of the infiltration to go right through the soil profile then the other extreme poorly drained here is where you have more silt and Clay particles which slow everything down and you get a lot of R
Runoff and infiltration so let’s examine those two systems more clearly the fast infiltration system what do you get soils and subsoils are well drained the rock also helps water move underground think of carer productive bedrocks here though you get low amounts of runoff you won’t find a lot of infield drainage
Systems are open ditches the dominant pathway is subsurface right down into the groundwater and things like roadway networks are quite low in density the nutrients lost here will be nitrate remember in the web series car Richards covered nitrate phosphorus also to groundwater Karen Dy cover that topic
Very well mitigation here look at source and mobilization control right across large areas now look at the slow infiltration system here it’s harder to move water through the surface and it goes more over the top we are changing our landscape all of the time we are speeding up water on
These Landscapes here poorly drained mineral are indeed PT soils the rock underlaying is poorly productive it’s less permeable here now we’re going to get lots of runoff we’re going to have lots of infield Drainage Systems which move water we’re trying to trick the soil to to tell it it’s better drained
Than it actually is we have open drainage networks and the dominant pathway will be surface but also shallow surface through these drainage networks the roadway network is quite dense in these systems and it’s more about phosphorus but we shouldn’t forget nitrogen nitrate goes into drainage systems and it gets converted in these
Heavy soils to ammonium so we must think of ammonium leaving these systems as well here we need to break the pathway and that’s very very important in these types of systems but remember at catchment scale all of these extremes and indeed all of the middle ground is completely mixed in
When we get to C scale we conducted a literature review some years ago and we looked at how long it would take for practice change to knock on to water quality change and we looked at catchments up to about 100 km squared 25 studies were included and it results are
Quite interesting positive effects were found in 17 of the 25 catchments but it took long time for things to to appear in the monitoring Network up to 10 years for a positive response to show up and it took longer as the catchment got got bigger and here again is the big Point
Response time increased as a transport pathway increased and also there’s not only a natural time lag but also a time lag in terms of implementation of measures so what we find is we have two systems the slow infiltration system with time lags of weeks to months and here we must intersect surface Pathways
Karen Dy calls these pinch points and we must go after these pinch points in terms of fields drainage roadways Etc and intercept the nutrients the sediment being passed on into surface water then we have a fast infiltration system here time lag is much longer months to decades we have programs of measures
That look at diffuse losses but we need to manage our expectations here because of the length and the commitment required to change let’s look at this red circle here there’s a lot going on in that in that underground Black Box almost we sure have nitrogen surfaces leaving our systems but these surfaces
Feed as nitrogen storage component underground and I call them biogeochemical time lags we must attack that storage component and therefore have not gone benefits for a water my research looks at land drainage quite often and water quality response to different land Drainage Systems in Ireland we have two systems at play
Shallow systems that Target rainfall and deeper systems that Target that Rising water table all of the systems that we’ve looked at have sediment carbon phosphorus and ammonium loss not nitrate but ammonium in Ireland now let’s look at drainage research going forward we need to focus on Mineral and not Peete soils we need
To avoid drainage in some landscape positions like flood planes and we need to break the connectivity of drainage networks with things like farmyards roadways and surface water and let’s look at an example currently being made I suppose out there on the landscape I see a lot of gravel being filled up
Right to the surface in Drainage Systems which is goes against practice okay why the top one is the perception that’s out there if you look at it it shows that water is just moving to a pipe drain directly overneath the disrupted area and that’s actually an incorrect way of looking at drainage you
Actually get uniform flow into the soil and lateral movements to a pipe which means we actually need less dense Drainage Systems out there and indeed there is no point in filling up your drainage system right to the surface with gravel it introduces environmental problems but from a hydrology and water perspective it’s
Absolutely I’m not going to dwell on this bit too long because D is going to get into it more but diffuse critical Source areas of tree components small or large pollutant Source here again it’s not about how big the source is but it’s the load of nutrients being lost from The Source if
We have a high mobilization risk and then an area with hydr ically sensitive area this means that lots of runoff can occur there’s connectivity of this runoff delivery to a surface water pathway and we need to break the the pathway again in these areas a new pathway which I am doing a
Lot of research in is in the Road Runner the EPA Department of egg funded project and it looks at Farm roadways these are hydrologically sensitive areas research from New Zealand shows that phosphorus and is low on an annual basis from these roadways but but but if you look at
These in a different way during the summer months as I’ve indicated we are getting more and more rainfall and more episodic rainfall events and the study in New Zealand showed that from these hard surfaces you get a huge proportion of losses during the summer months which was going to become more and more
Interesting in Ireland so therefore we need to divert roadway runoff into our Fields away from from ditches and away from surface water bodies if you think about it animals walk on roadways and contribute phosphorus nitrogen and indeed eoli through defecation so on my final slide I want
To leave you with breaking the pathway and some examples we need to divert water off our roadways into fields and dar is going to look at more U of what being done in fields and use Simple structures to divert this water at regular intervals on particular sections we need to
Consider engineered options in our open ditch systems for example where we guide our Drainage Systems into our open ditch systems and we treat we drop the sediment we slow the flow we release um we drop carbon we drop nitrogen and we drop phosphorus in our open Channel systems before they affect uh surface
Water quality and with that Mark I can hand over to you again thank you very much thanks very much Owen uh excellent overview of the issues and and that connection between uh the the the the source and the pathway so Dar you’re going to give us a an overview some of
The um the mitigation options available are being being uh explored um and we’ll take some questions then afterwards so over thank you Mark so hopefully you can see this screen now so as Mark says I’m going to give a a brief presentation on sediment and water quality as a background we’re
Pretty familiar now over the last few years in relation to water quality H we’ve heard presentations here as part of the signpost series and we’ve seen reports from the EPA highlighting the decline in water quality over recent decades we’re familiar with various pressures impacting on water quality we
Have a good enough handle on the story in relation to nitrates or phosphorus as own was was presenting on there as well what is less clear is the impact in relation to sediment and how sediment is impacting on water quality we will hear later on this month probably in relation
To ASAP or law Pro that they’re encountering sediment as a more significant challenge than we hear for believed it to be in relation to impacting on water quality the other challenge with sediment is that it’s not really included that well in relation to our water framework directive
Assessments and there is we are unclear really in relation to what thresholds for set sent should be within our systems so as a brief background well what is sediment well sediment is a natural phenomenon H it deres from the weathering of rock or mineral organic or soil material over time that can make
Its way into a water course land juice can accelerate soil erosion and can result in the delivery of of excess sediment to these water courses and various different types of land use can become a source of sediment such as bare soil from from plowing or from receding cattle access points or cattle trampling
And poaching river banks can provide a a ready source of sediment adjacent to a receiving water bodyle but then also other land juices such as as poorly cited forestry on shallow soils adjacent to a water course can also become a source of sediment because of windthrow and the available root Source associated
With some of this land juice so when these excess sediments become a a problem then we need to start looking at mitigation and further down the line so what really constitutes excess sediment so a way to look at it is looking at the sediment yield from a catchment that’s
Making its way from the terrestrial landscape into the water course so the yield from the land making its way into a water course and numerous Studies have been undertaken on this throughout the world and the way they generally look at it on on the x-axis here we have catchment size of varying catchment
Scales in kilometer squared and 1 kilom square is 100 hectares and then on our y AIS we have the yield in tons per kilometer squared so how much of the sediment is in Catans of varying sizes and up until recently there’s been a pretty good idea and plenty of research
In relation to various different countries throughout the UK and throughout Mainland Europe as well ac across various scales of Catman size resulting in a diversity or a variability in relation to delivery or the sediment VI Within These cats relatively less was known from an Irish landscape up until relatively
Recently so in the last couple of years we’ve looked at sediment yield associated with five of the ACP or the agricultural catchments program catchments and these are intensive catchments we saw that the yield range across these five cats from about 8 tons per kilometer squared up to about 25
Tons per kilometer squared so there’s variability between these catchments but then even within the catchment there’s variability as well so these figures are BAS based on three to four years of data that were averaged out but even from year to year within the one catchment we’re seeing variability and these are
Intensive catchments but we’re still seeing that they’re significantly less than similar studies on similar catchment sizes throughout Europe when we start looking at some of our extensive catchments and these are studies that were undertaken by us down in the Freshwater Pearl muscle catchments down in Kerry the sediment
Yield per kilometer square is very low down to less than three tons per hectare in some of these very very extensive catchments so we’re seeing that Irish situation even though it is a challenge and it is a problem it is less than what we’re experienced elsewhere in
Europe when we delve a little bit further into our intensive catchments and our ACP catchments there are two significant drivers you’d expect to be influencing a sediment yield in these water forces you’re looking at soil drainage class as own mentioned previously from from well drained to poorly drained and you’d also expect
Land juice to have an impact in relation to the sediment yield so the difference between let’s say grassland and arabel so when we looked at the five ACP catchments they were broadly split into two a land juice types three of which so three craftland catchments and two arabel catchments and then were split
Between poorly drained to well- drained and what we’re seeing in this graph here is regardless of the land use type when we’re looking at well- drained soil there’s pretty similar sediment yield associated with these land use types at a Catman scale over 10 over 10 tons for
Our arble just under 10 tons for our grassland similarly at our poorly drained catchment there’s not that much difference in relation to the sediment yield between the land use type again about 24 25 tons per hectare for both arable and for grassland so where we’re seeing a significant difference is in
Relation to the soil drainage class when we’re comparing our arable catchments between poorly drained and well- drained soil poly drained up by 25 tons per hectare down to well drained up by 12 tons per hectare a significant difference between the to and similarly within our grassland land use between
Poorly drained and grassland or poorly drained and well drained we’re seeing a significant difference so now that we know that there’s a difference in yield between different catchment types even if they are all the One intensive land use or or between main land juices what are the main sediment sources that we’re seeing
Within These catchments so we undertook this thing called sediment finger printing to try and identify the various different sources of sediment that are making their way into the water Forest in our poorly drained grassland hpe as we said about 24 tons per kilometer squared we’re seeing that 70% of the
Sediment is derived from the channel Bank are from the drainage open drain ditches and and the banks of the open drains when we look at this on a seasonal basis as own was saying as we’re seeing most of the rainfall over the winter Mo months this is also
Coinciding with most of the sediment delivery this is because soils are becoming saturated there’s more intense rainfall but also more intense rainfall results in more intensive flow within the water course result in in Greater erosion of the river banks and also there’s less vegetation on the river
Banks to protect against some of this scour when we look at our Arab catchment again half the amount of yield that we were seeing in our poorly drained grassland but similarly we’re seeing 60% is derived from the channel now where we’re seeing significant difference here is in our Arab and poorly drained soil
We’re seeing 75% of the yield of this 25 tons per kilometer squared is derived from field top soils and again when we look at this on seasonal basis these are our winter months here most of the sediment is being transported in our arable catchments during the winter
Months in both occasions and as own said it’s coinciding with periods of intense rainfall and also coinciding with periods post Harvest when you have a bare so so you have a readily available source of sediment and then youve the rainfall to mobilize the sediment and it can make its way into the water
For when we look at our sediment sources in our extensive catchments again it’s worth noting these are very very extensive Catman three of which are down in carry so the brida the on Ru and the Keel Duff we’re seeing differences in relation to the sediment shield and the sediment sources between the different
Cents again scale of sediment Y is very low 2.7 tons for our own R up to about 5 and a half tons for our Bria but again from a European context that’s very low the channel Bank as a source is relatively similar between the three Catman types where we are seeing a
Significant area of interest is in relation to this kind of yellow color which is our improved grass land and so improved brassland across the Catan types is delivering about 20% of the sediment yield even though it only constitutes about 5% of the catchment area so that’s that’s significant the
Other area of interest is in relation to forestry so for the own R and the KE there are elements of or there are areas of Forestry within the catchment and we’re seeing that this forestry is a significant source of sediment despite the fact that it’s established historical and by and large unmanaged
Forestry but because it was poorly located in the first place 30 40 years ago it is still a source of sediment 30 or 40 years later so what is the impact of this sediment on our ecosystem on our ecology or on our streams so by and large sediment has a physical impact in
Relation to the riverbed habitats so it can result in clogging of gravels and reducing the dissolved oxygen within the riverbed and this has a significant impact on many of our more sensitive species and some of our indicator species such as the Freshwater Pearl muscle that need clean well oxygenated
Gravels to spawn and to live similarly for some of our salmon OD species sediment can also when it’s in suspension result in turbidity so in cloudiness of water as we’re seeing here adjacent to a cattle access point so this can reduce light penetration through the water colume which is
Impacting on primary production within the water course but it can also impact on feeding of fish and on invertebrates General and specialist invertebrates such that they can feed appropriately and again it impacts on the Ecology of the ecosystem more recently we looked at a a study to assess the difference between
Sediment and other stressors within a water course and we set up multiple stressor experiment we mimicked Channel beds using these trays that were continuously fled fed with water from a nearby River we manipulated sediment phosphorus and nitrogen individually and combined and then we replicated the stream bed by putting in gravels and
Stones to replicate the stream bed and we inoculated it with invertebrates and we assessed the response of the invertebrates to these various different stressors and as a very brief summary for a very long experiment the conclusion was that sediment under these systems was the most significant stressor on aquatic
Ecology so now that we know that there’s a source now that we know that there’s difference in yields and now that we know it has an impact on ecology how do we go about mitigating against the challenges associated with SED and you are familiar probably with this Triad of
Source pathway and receptor where we have a source such as soil where we have a pathway such as Overland flow and where we have a receptor such as a receiving water when you have all three of those you have a risk if you remove any of the tree then you remove the risk
Remove the source or remove the pathway or remove the receptor then you no longer have the risk so for the remainder of the presentation we’re going to focus on the pathway as own mentioned how do we break the pathway to stop sediment getting from the source into the receptor and we’re going to
Focus specifically on riparian Buffer strips so riparian buffer strips are bands of land adjacent to water bodies that are planted with permanent vegetation the theory is relatively straightforward you have saturated soil as own said where you have Overland flow or Surface flow this surface flow containing nutrients
Or sediment or pesticides then meets the buffer strip and the vegetation within the buffer strip intercepts the pollutant through sedimentation or infiltration or dilution and prevents these nutrients from making their way into the water of course and that is fine in theory when you have uniform Overland flow but what about situations
Like this where you don’t have uniform Overland flow where you’ve undulations within the landscape and you’ve areas of converging and diverging flow such that flow is channelized in certain parts of the field and makes its way down to the water course when it gets to the buffer strip because of this channelized flow
The buffer strip becomes inundated so it can’t cope with the amount of flow then also youve large sections of the buffer strip that aren’t subjected to any Overland flow so there’s relatively little buffering going on here we see an example from a catchment with a relatively modest slope and it has a
Riparian buffer strip following gaec guidelines two meters wide but because we’ve had poorly drained soil we have a source of sediment here in relation to the bare soil we have intensive rainfall which is mobilizing this sediment and now you have an Overland flow pathway and a receptor so despite the the
Presence of a buffer strip because it’s poorly managed and poly cited in this occasion the sediment is making its way into the water for so that leads us to smarter buffers a new project that in collaboration between chask and the James Hutton Institute and funded by the EPA and
We’re looking at designing and managing buffer strips and targeting them to these hydrologically sensitive areas as own mentioned and it’s going back to this idea of a right measure in a right place that we’ve heard over the last number of weeks as part of these sign
Post Series so what is the right place or how do we about identifying the right place for some of these riparian buffers well you can use technology such as liar technology to identify areas of elevation within the landscape so you can identify elevation but also you can identify depressions within the
Landscape so you can see where there’s going to be Overland flow you can overlay L maps in relation to potential sources this is a map of P for example so high P index could be a source of P but you could do similarly for sources of sediment such that you have your
Source on on on the right hand side now you have your potential pathway on the left hand side and when you combine the two you can start seeing these flow Maps where there’s Overland flow with a source you identify so this some work that is being done by diffuse tools
Which is again being funded by the EPA you identify areas of flow you identify delivery points such that if you then Target your mitigation to these delivery points you can reduce the the cost of implementation of typical traditional linear riparian buffer strips equally importantly you can start identifying natural mitigation features you can
Identify depressions within the landscape that are acting as kind of sediment traps or ponding within the landscape temporary ponding such that sediment falls out of suspension and it doesn’t make its way into the water Forest you can also identify natural mitigation features such as areas of
Scrub or areas of Woodland many of which are ineligible for single Farm payment but are playing a very important role in this instance in relation to mitigating against water quality and delivery of sediment along with other ecosystem services such as biodiversity so by characterizing the flow we can use the information that
We’ve gathered in relation to the right place to start informing information in relation to what is the most appropriate measure for this right place so here we have a a flow map for one of the catchments as the ACP and you’d expect one of the fields here has relatively
Uniform Overland flow you’d expect a mitigation measure that you Target in this instance is going to differ significantly from the mitigation measure you’re going to Target on the bottom instance where you have more periodic but channelized flow so now that we have an idea about the right place how do we go about
Undertaking work in relation to the right measure and riparian measures are widely implemented and have been widely implemented in Ireland through compulsory or optional measures over the last 20 or 30 years we’re familiar with the good Agricultural and environmental conditions stipulation for 2 meters wide and no fertilizer and no pesticide or
More recently 25 years of Agri environment schemes from reps to AOS to Glass again have linear riparian margins where there’s no fertilizer or pesticides and more recently where they’re recommending no no stop access but by and large policy in this area has been relatively conservative in relation
To riparian design so we have seen various widths from 3 m to 30 m for example in relation to Glass but why don’t margins are not very popular and there generally are frequently a low uptake amongst participants equally wider margins are not necessarily more effective at buffering than some some of our narrower
Margins the buffering ability of our riparian margin kind of Maxes I over a certain width most of the buffering starts in the first few meters and over a certain width beyond that width of 10 20 or 10 15 or 20 meters there’s relatively little additional buffering now The Wider margin will have benefits
For for biodiversity or could have benefits for carbon storage but not necessarily additional benefits for water quality equally as we’ve saw with our right place if these wider margins aren’t targeted to the right place then it’s not going to have additional buffering abilities so we need to start exploring alternative management alternative
Planting alternative design for our riparian margins and again this is some of the work that we’re exploring as part of the smart Bice project so there’s a variety of different mitigation measures that we can Implement at Field farm and Landscape scale we can assess and we’re
Hoping to do this with part of the smarter buffers what is the impact of undertaking just a regulatory minimum just a 2 meter wide margin with no pesticides and fertilizer application what’s the impact of that on water quality when we have gathered other information in relation to Overland flow
And in relation to some of the potential sediment or nutrients that could be delivered to the water course we can compare this regulatory minimum to linear grass buffer strips that are wider now maybe 6 MERS wide as opposed to the 2 meter wide that we have for our
Regulatory minimum we can then explore what’s the impact if we exclude cattle in relation to this so now you’re improving the the water quality benefits but you’re limiting a you’re also improving Limited additionality in relation to some of the habitat Improvement you can start expanding further you can start managing the
Different vegetation or planting different vegetation in relation to these buffer scrips so grasses have benefits for certain nutrients whereas trees and scrub would have benefits for other nutrients and for sediment and you can start comparing the differences between the two and you can come up with a variety of different riparian
Managements and establishment techniques such that you can start treating the different stressors be the sediment or nutrients within the landscape and you can start moving down towards denitrification buffers towards buffers that can Target more soil erosion all the way down to buffers that are going to intercept subsurface drainage which
Most of our traditional linear buffers neglect to do so so you can a variety of different techniques that can be targeted specifically to the landscape that the buffer is going to be targeted within and also consider that the pollutant that the buffer is hoping to address now it’s important to note that
All of these are going to have a different cost associated with them and there’s also going to be different levels of acceptance so you can imagine that the cost associated with undertaking the regulatory minimum is going to be different than the cost to undertake some of the measures that down
At the bottom of this table where there’s High management measures and more land use might be needed to undertake this measure so there’s obviously going to be an Associated increase cost on the flip side you could imagine that there’s going to be reduced acceptance As you move down the scale
It’ll be more difficult for some land owners and policy makers maybe to accept some of these suggestions so the undertaking the regulatory minimum has wide acceptance but as you move down to more highly managed and more specific and targeted riparian buffer management designs the acceptance might wi so it’s
Important that we start Gathering some of this information or hoping to do this as part of smarter buffers that we work with the various stakeholders it be it in policy or research or with farmers and advisers and water managers such that we can get gather the relevant and the appropriate research that’s required
We can identify some of the stressors that are in the landscape and we can work with land owners to see what would be acceptable or what is practical and when we’ve all of these various stakeholders engaging with one another then we can start designing appropriate smarter buffers for the right measure in
The right place so Shin Shin so thank you and back to you mark Dara thanks very much for that excellent presentation and a really good overview of of how the different measures can operate in a policy context because often times we you know there are measures investigated uh with not really
Proper uh attention paid to the acceptability or the cost associated with them uh Dara just noticed in your presentation you focused very much on the the pathway uh and receptor part of of the the the process what about the source side of the the process is there
Much work uh done in terms of what what we can do to reduce um the source of of sediment I know for example in a a tillage environment or arable setting that you know contour plowing and those types of measures are are available and used in in some countries um what sort
Of measures are are being recommended uh within either Aral or or grassland setting or is there much that can be done there there is stuff that can be done obviously so again if you can reduce the sources of the sediment such as bare soil then you can reduce the
Amount of sediment that’s making its way into water courses we are behind other European countries probably in relation to some of these measures being Incorporated in agre environment schemes H as we’re seeing and as own mentioned when soil is saturated and most of this is a curring during the intense rainfall
Of the winter months if we can reduce the amount of sediment that’s available during these winter months such as we’re seeing with our Arab land such we don’t have bare soil such you have green cover for example to reduce the source also mitigation measures such as trying to
Avoid targeting arable land to these areas of poorly drained soil because it’s more readily available or it can make itself available and then another area to reduce the source I suppose is we’re seeing with cattle access points where you have catle access making its way into a water course then that’s a
Source and a delivery pathway so if you can remove some of these cattle access points you can reduce the amount of sediment that’s making its way into the water for thanks Dara ohen you talked a lot about these uh increased uh prevalence of of intense rainfall periods during
Summer months uh we’re likely to see more of that in the future according to the the climate uh change uh scientists that we’re going to see more intense weather events you know what does that uh uh lead for the the future of of um how do we manage those future events uh
If if um we’re to to manage or to farm uh without having an impact on water quality or to minimize that impact yeah well I suppose the the important thing to think about is we’re getting about the same amount of rainfall in the year but the distribution is
Changing let’s say in WX we get about a th000 Ms of rain one meter of rain if you want to think of it like that normally as Dar was saying we’re hydrologically active period being from September you know all the way to to to April but what we’re finding take this
Year as an example we have very very dry periods the last week has been very wet and it’s July right um so these things are changing and that means very very different things summer months we actually think of the groundwater system being slightly disconnected so in other words we’ve had less
Rainfall the water table is decreasing down and that breaks the connectivity so if we’re now introducing rainfall events in the summer periods other Pathways can become active mentioned roadways for example um if we get uh you know rainfall onto hard surfaces um and those ra roadways are connected to open
Ditches and directly to surface water bodies a small amount of rainfall could mobilize new nutrients very quickly into rivers same in open ditch systems um you know a very very small rainfall event can contribute some nutrients so we should think of these things as loads you can have a small nutrient Source but
The the rainfall can mobilize that and the load or the shock effect could be high in a very small period thanks Owen um I mean that the design of roadways is really important so uh in that case you know to reduce that the I suppose the the energy and
The speed of which water is Flowing on on water ways and in fact Chagas has um Incorporated this into some of the training that we do around farmyard design uh with with Agri professionals I suppose also a good opportunity to flag the chagus offers a land drainage course
A uh an accredited course in in land drainage for professionals who are designing drainage systems that they are done an appropriate way I suppose from both of your presentations it’s very obvious that a tailored approach is is what is required at a farm level that’s having generic uh recommendations just
Doesn’t work because we have such a uh diverse uh soil types and and Landscape types and so on would you agree Dara that maybe we do need a bit more training in in these areas particularly around riparian designs designed for agre professionals or those working in in the agre food sector absolutely I
Think we can provide research and we can learn from research throughout Europe where are a bit more advanc in some of this work but I do definitely think that we can need to start disseminating some of this research and provide training to advisers or to partitioners through
Farmers as well so some of the the work that we’re hoping to do with smarter buffers is to come up with these decision support tools for policy makers but also for advisers and Farmers out in the field so it can kind of disseminate or the the wide range of science that
Behind the decision support tool can be made in a more kind of a manageable approach so that they can use this tool to identify what’s the likely source to identify what type of Hill slope they’re managing on and then they can use this to reduce the number of measures from
Maybe eight or nine potential measures down to two or three measures that would be most suitable for them has I see a few questions coming in through our uh the Q&A uh section there some some questions uh just remind everybody that that facility is open now
If you want to subit your questions uh please do send them through to us yeah and I think a number of questions in in the whole area of of of policy and given the fact that we have uh a review of the the cap and and potentially coming in
Under ecos schemes and and agre environmental schemes are there a number of if you’re having a conversation with the with with the policy makers are there a number of areas that you would uh focus on in terms of of uh trying to was change the way we do policy and and
Other the things we should be focusing on so what I let you go first on or I don’t mind there so I think for me there’s a few very very interesting projects um you know EA funded projects in particular and some co-funded with Department of a darz in a few a few and
It’s really about you know where are the priorities on farms in terms of this over you know these I call them slow infiltration systems okay so they’re very much pinch points on the farm and again trying to slow the flow if you think about our Landscapes we we
Have done over the Millennia we’ve tried to speed up water leaving our Landscapes right it makes makes common sense that if we can get water away faster we can then you know farm the land more efficiently Etc but now what we’re trying to do is I suppose
Slow things down to a certain degree okay if you slow stuff down you’re you’re controlling the load of nutrients leaving the system and therefore we need to start looking at different parts of that infrastructure within the landscape differently open drains for example is one of mine um my things along with
Karen Daly really thinking about you have huge opportunities in areas like that in terms of droing sediment like darl was saying but also car carbon in that sediment carbon very very important on our agricultural systems and then decreasing the load of nitrogen and phosphorus in those systems um roadways
May be new here but it certainly isn’t new in other parts of the world and breaking that connectivity so it’s incorporating these these channels or conduits for loss into Agri environmental schemes Etc uh where we can then Implement change we can intercept the pathway and you know minimize minimize the load of these
Things to surface water um and I just want to say one thing as well is that with all of these engineered Solutions you’ll never minimize absolutely 100% a lot of these systems are designed with a targate amount in in mind such as about for nitrogen for example or phosphorus typically only about
30% of the the load would be treated in this way so we need to be cognizant of you know really taking care of business right across the landscape find these pinch points and attacking them headon and what always remembering to take care of everything uh first and then managing our
Expectations about how long this is going to take it’s a long-term commitment um mitigation is a long-term commitment and some of these mitigation measures will also need maintenance uh by land owners I just come in there as well and again building on what own said in relation to our our drainage Network so
We’ve had 30 years almost now of Agro environment measures and we’ve had very few measures that are specifically targeted to drains so you if you would imagine that here’s an area where you could explore the inclusion of in drain treatment the land is already removed from production so it might be more
Acceptable from a landowner’s point of view to Target some of your measures and then as own said you could have these multifunctional measures so they’re still facilitating the role of a drain to help in relation to the productive element you can manage it for water quality but then you could also manage
It from biodiversity and a carbon storage point of view for land that’s already removed from production in relation to policy P well another area that I do think needs a consideration is in relation to these areas that are already removed from from eligibility such as certain ponds C certain areas of
Scrub a certain scrubby buff buffer strips that are already there that might be ineligible for your single Farm payment even though they’re providing a multitude of ecosystem Services the farmer is is kind of perversely encouraged to remove them because they’re losing out on their single Farm payment so that’s an area that policy
Could explore not just from a water quality point of view but also from a biodiversity and a carbon point of view as well okay there’s a a couple of questions in the whole area of of stocking race and and in terms of of uh the the nitrogen vulnerable zones or the
Fact that we have a single zone in Ireland um is uh is there an element to which stocking rate is is um has is having an impact or is it more down to to Land Management around those stocking rates in sorry well from from a a sediment point of view so anything that
Can create or result in a source of sediment such as bare soil can can influence the amount of sediment you that’s going to be in a water course so if stocking rate adjacent to a water course is resulting in PO on PO drain soil is resulting in poached soil
Adjacent to the water Force well then that’s going to be a challenge for water quality as I mentioned previously where stock are G making their way or getting access into water courses not only are they destabilizing the bank but then they’re also turning up bed sediment as well so
That’s influencing the amount of sediment getting into the stream but also degrading the bed habitat as well so there’s there’s challenges and there’s there’s difficulties associated with that as well that’s what I can comment in terms of um you must think of the landscape in two different ways again you know the
The the across the surface versus is the the vertical pathway when you think of this so um but myself and Dara looked at the critical Source area it’s all about load okay so you can have in the surface Pathways you can have small concentrations but a large amount of
Water that’s really the same as a large source with a small amount of water it’s about the the total um I suppose kilos of n or kilos of P leaving that pathway in terms of infiltration there is a direct you know correlation the the higher the load the higher the Surplus
You know at one meter so that nitrogen Surplus is very very important to we need to decrease the Surplus leave meter Zone that feeds this tank I I I I kind of called it it’s like an off account of nitrogen in the subsurface we need to influence that and that’s the store of
Nitrogen that will influence water quality in groundwater and in surface water and there is not a direct correlation between end Surplus and water quality and it’s very much soil type driven you can have the same Surplus in a free drained and a poorly drained site but the result in terms of
Water quality can be quite different and that’s where a lot of research I think needs to go into it’s that black box the organic nitrogen component we need to know an awful lot about that it’s not a steady state relationship it’s a very very dynamic system and we need more
Information and knowledge in that in that area with a question here in relation to the suppose measuring the success of these mitigation measures how how many tests or how often uh and and when what about before during and after high rainfall I know we have the agricultural
Catchments program and then we also have the H the asip program which has uh monitoring that’s going on there I mean but if we were to look look at I suppose I I guess this question is in the broader context if we’re looking at measures coming in through an agro
Environmental scheme how can we be sure that these measures are working and having the desired impact okay so again we can we can learn from work that has been done aswh Ireland as I said is a little bit behind some of our European counterparts in relation to exploring these mitigation
Measures and significant work has been undertaken in Europe looking at the the efficacy of various riparian treatments other than just the traditional long linear buffer strips so then you can see we can learn from those measures also we need to be familiar with moving away from the one size fits all approach to
The more targeted and bespoke measures depending on what the nutrient or depending on what the sediment threat is to the water hor and then also depending on the soil type of the land use because as Owen said you’ll have different areas of flow so I think we have enough
Information to start learning from what has been done elsewhere such that we can build on the work that other countries have done and learned from some of their mistakes such as Denmark which implemented a wider riparian margin as a uniform measure and it didn’t really have great uptake and was unpopular
Amongst landowners and then it was deemed to be an inappropriate measure in the end so we can learn from what other countries have done in this regard question here in relation to the I suppose the evolution of advice over the last 30 years in relation to drainage um I know some some
Commentators have called it the the highway for for NE nutrients and sediment to access our water courses um and the what the question is here is H do you think chagas’s advice to Farmers has been appropriate over the years um and when uh we see when we see so much
Drainage work continuing on farms uh and so poor buffer zones I guess the question is here and it links into my earlier comments about the land drainage course that’s an offer where it talks about appropriate drainage uh system but I I think it’s fair to say that the message has evolved significantly since
Uh 30 years ago on yeah I think uh what I really should say is that the knowledge was always within the organization you know long before I started the I suppose it’s the roll out of that information in other countries if you think about contractors that install drainage systems would have gone
You know would have been trained appropriately in drainage so management so what myself pouille especially in MO Park would have decided that we needed drainage manual first off uh which certainly will be updated over time it needs to be updated um but the course really takes on a variety of people
Farmers land owners but also we’re trying to you know contractors themselves and what we found in the past was that drainage was just implemented right across the landscape regardless of soil type that was the major drawback of our method so in other words what your neighbor did I will do what I completed
In one field I’ll complete in the next field and this has led to inappropriate land range designs right across the country now there is an eia in place um in other words that new land drainage um jobs there is a screening process so people be cognizant of that and that is
Very cognizant of En enironmental um issues um so what I what I’m I suppose constantly um advocating is drainage but drainage appropriate drainage correct installation correct drainage um spacing and in the correct location and going forward we really really need to start thinking of the environment um and the
Role of draining systems in you know um releasing nutrients and carbon um to surface waters and we really need as darra was saying we can use the the infrastructure that’s there it’s not going away these are installed systems we need to adapt them and we can use
Them in an environmental way in terms of mitigation using open ditches slowing the water down water table control also has greenhouse gas emission potential and looking at drainage in a different perspective and that’s where the research is going now thanks um we’re getting tight on time now Pat were there
Any burning questions that you want to a couple of questions in relation to the uh type of of plant material or plant growth in in buffer zones what’s what’s best is it’s best just left of its grass or and then the role potentially of uh Forest strips uh uh for
Buffering yeah so again this comes back to what is the stressor that you’re trying to prevent with your right Aran buffer for some of our sediment and particular PE associated with sediment when you have a dense vegetation you have greater infiltration and greater intercepts of the sediment and that was
Probably some of the challenge with previous schemes such as reps where you had you you fenced off your margin and you didn’t manage it thereafter such that you could have a gor or something dominated the riparian margin which had a very low under story growth and very
Low vegetative layer such that it wasn’t really intercepting so you need dense vegetation but then again for some it’s important to note as well you need to harvest if we want to remove the pee from these systems you need to harvest the vegetation you need to take the pee
Out of the system and the most appropriate way of doing that is to take the vegetation out or to harvest the vegetation with the pee the pee doesn’t break down over time like some of your nitrogen or some of your or some of your a pesticides so it’s important that you
You harvest and manage the riparian margins appropriately depending on what the stressor you’re trying to intercept is okay thanks Dara uh unfortunately we’re going to have to leave it there but some really interesting questions that we didn’t get a chance to to tackle were you know the role of uh ponds and
And in the landscape and so on so maybe we could deal with that in a future uh webinar but for now uh darra hulakan on Fenton thank you very much for your presentations P thanks for assisting with the uh the the questioning and also a big thank you to Ivon Maher and Andy
Boland who are uh our production team on the webinar series I also want to give a special thanks to uh Brendan Dunford and paty curan here based in the the Buren in County Clare for facilitating me this morning to to broadcast from the Buren so uh big thank you to both py and
Brendan for that reminder that today’s uh webinar is being recorded and will be available on the chask YouTube channel in the coming days along with the presentation uh next week uh I’ll be speaking to Ruth Hennessy from the local authorities water program we’ll be talking about uh protecting natural
Waters through a catchment management approach so uh we’re looking forward to to talking to rots uh at the same time next Friday so for now thank you very much for tuning in and we hope to see you next week thanks again you’ve been listening to the podcast version of the chagus signpost
Series The Weekly webinar that promotes and examines sustainability in Irish farming don’t forget to join us live every Friday morning for our latest webinar for more visit Chagas and you can also rate review And subscribe to the signpost series on Apple podcasts Spotify or wherever you get your podcasts from I’m Mark Gibson
And thanks for listening