Skip to main content

Listen to our panel of experts discuss how building a robust contaminated site model can give you a solution that’s safer, faster more certain and easier to defend.

This webinar covers:

  • Bringing teams and diverse technical expertise together to see the full picture and build a collaborative solution.
  • Discovering where the contamination lies – in groundwater or soil – and defining how it affects your project.
  • Maintaining a clear, data-driven plume interpretation that will stand up to interrogation.
  • Making data work harder and smarter, and use powerful 3D modelling to tell its story clearly and concisely.
  • Arriving at a solution that is effective, transparent and defensible; one that can react quickly to the latest updated information, and allow for informed engineering decisions.
  • Communicating your decisions in a way that makes client and local communities feel confident in the direction you’re taking.
  • Providing reports that will satisfy regulators and help your client meet legal requirements with confidence.

Dr Amir Niazi, Hydrogeologist/Groundwater Modeller, Matrix
Experienced hydrogeologist and groundwater modeller with a history of working in the environmental services industry. For the past 17 years, he has applied and expanded his skills with regards to local and international water issues. Has developed a range of numerical and conceptual groundwater models for contaminated sites using his knowledge in hydrogeology, geostatistics, single and multiphase flow modelling in porous media, and surface water modelling. PhD focused in Geological and Earth Sciences/Geosciences.

Dr Thomas Krom, Segment Director, Environment, Seequent
Has been involved in the development of Leapfrog software since 2007 and now spearheads the strategic direction of Seequent in the environmental and sustainability areas. More than 30 years’ experience in the geological sciences gathered from around the world. A skilled groundwater modeller involved in a range of consulting and research projects. PhD, Civil Engineering and Master of Science, Geological Engineering, with both qualifications involving significant research into methods to describe and optimise geology statistically.

Tim Schurr, Solutions Architect, Seequent
Responsible for exploring, imagining and creating new innovative solutions to support Seequent’s customers now and in years to come. Nearly 20 years’ experience in the software industry with a passion and speciality for geospatial products. Extensive experience in working with locally and internationally distributed software teams, with familiarity in surveying, roading, tunnelling, survey instrumentation, geology resource estimation and 3D visualisation. Bachelor of Engineering, Electrical and Electronic Engineering.

See more on demand videos


Find out more about Seequent's environmental solution

Learn more

Video Transcript

[00:00:04.563]<v Tim>Good morning, good afternoon, good evening</v>

[00:00:07.430]wherever you’re joining us from today.

[00:00:09.356]This is Taming the Complexities of Contaminated Sites.

[00:00:13.693]This is a webinar brought to you by Seequent

[00:00:16.847]and brought to you by Matrix Solutions.

[00:00:21.974]Today we will be discussing how to build

[00:00:25.179]robust contaminated site models

[00:00:27.722]which can give you a solution that’s safer,

[00:00:30.760]a solution that’s faster, more certain,

[00:00:33.700]and easier to defend.

[00:00:36.545]My name is Tim.

[00:00:37.978]I am a solutions architect at Seequent.

[00:00:41.670]And it’s my pleasure to be hosting this session

[00:00:44.341]along with our two experts today,

[00:00:46.847]and bringing your questions to them.

[00:00:51.329]So let’s get to know these experts a little more.

[00:00:54.282]And it would be remiss of me not to introduce myself first.

[00:00:59.930]So I’ll start there, my name is Tim and I work at Seequent

[00:01:04.556]on New Product Development.

[00:01:08.010]In the past, I led Leapfrog Geo to market in 2013,

[00:01:12.270]and then in 2016 I did the same with Seequent Central.

[00:01:18.260]I’ve got quite a passion

[00:01:19.400]for geospatial and geological products,

[00:01:22.040]but today I’m really excited

[00:01:24.712]to be talking about the challenge

[00:01:26.540]of complex contaminated sites and how we deal with them.

[00:01:32.480]So let’s look at our experts.

[00:01:37.000]First of all, I want to introduce Dr. Amir Niazi,

[00:01:41.625]and he is a hydrogeologist and a groundwater modeler

[00:01:45.900]at Matrix Solutions.

[00:01:47.846]Amir is an experienced hydrogeologist

[00:01:51.111]with a history of working

[00:01:53.390]in the environmental services industry.

[00:01:55.907]And for the past 17 years,

[00:01:57.810]he has applied and expanded his skills

[00:02:00.285]with regard to local and international water issues.

[00:02:04.231]He has developed a range of numerical

[00:02:06.810]and conceptual groundwater models

[00:02:09.074]and for contaminated sites

[00:02:11.037]using his knowledge of hydrogeology, of geostats,

[00:02:14.664]single and multi-phase flow modeling

[00:02:17.640]and porous media, and surface water modeling.

[00:02:21.224]And Amir holds a PhD in the Geological

[00:02:25.180]and Earth Sciences, in the geosciences.

[00:02:28.080]So welcome along, Amir.

[00:02:29.483]It’s great to have you with us today.

[00:02:32.021]You’re joining us from Calgary?

[00:02:34.127]<v Amir>Correct, yeah, thank you for that.</v>

[00:02:35.817]<v Tim>And I understand,</v>

[00:02:37.080]oh, you’re welcome, you’re welcome.

[00:02:38.370]I understand the weather is just about to change

[00:02:40.860]and you’re expecting winter to come

[00:02:44.190]with a thump pretty soon.

[00:02:45.921]<v Amir>Yeah, yeah, I think so.</v>

[00:02:48.550]I think it’s kind of overdue, the winter. (laughs)

[00:02:51.297]<v Tim>(laughs) It’s inevitable, it will come.</v>

[00:02:54.710]And the kids are just going back to school in Calgary now?

[00:02:59.630]<v Amir>Yeah, yeah, just started last week.</v>

[00:03:02.059]And, yeah, I think it’s a process,

[00:03:06.561]kids are going back to school.

[00:03:09.377]I think it’s fully opened today or yesterday,

[00:03:14.180]and all the kids are back to school at least–

[00:03:17.790]<v Tim>So a sense of normality returning there?</v>

[00:03:20.300]<v Amir>Yeah.</v>

[00:03:22.290]<v Tim>Well, it’s great to have you with us</v>

[00:03:23.820]and thanks for your time today.

[00:03:27.729]Next of all, I want to introduce Dr. Tom Krom.

[00:03:31.823]And Tom is a segment director currently

[00:03:35.120]for the Environmental Segment at Seequent.

[00:03:38.097]Tom has been involved in the development

[00:03:40.570]of Leapfrog since 2007.

[00:03:42.800]And now he spearheads the strategic direction for Seequent

[00:03:46.910]on the environmental and sustainability areas.

[00:03:50.501]Tom has more than 30 years experience

[00:03:53.580]in the geological sciences

[00:03:55.088]and he’s gathered that all around the world.

[00:03:58.285]Tom is a skilled groundwater modeler.

[00:04:01.424]He’s involved in a range of consulting

[00:04:03.390]and research projects.

[00:04:04.688]Tom holds a PhD in Civil Engineering

[00:04:07.530]and a master of science in Geological Engineering

[00:04:11.024]with both qualifications involving significant research

[00:04:15.220]into methods which describe

[00:04:17.540]and optimize geology statistically.

[00:04:20.848]Tom, it’s great to have you with us.

[00:04:22.597]You’re joining us from Denmark today.

<v ->I am.</v>

[00:04:26.610]<v Tim>How is the weather in Denmark?</v>

[00:04:28.848]<v Tom>The weather in Denmark is not bad actually.</v>

[00:04:32.220]At the moment it’s very dark weather, but, yeah, it’s cool,

[00:04:38.992]10 degrees, not raining at the moment

[00:04:42.100]though it rained most of the day.

[00:04:43.835]So we’ve definitely gone from summer to autumn here.

[00:04:48.869]<v Tim>It’s clicked in here at Claris.</v>

[00:04:51.690]The winter is coming.

[00:04:53.755]Hey, it’s great to have you with us, Tom.

[00:04:55.632]And thank you, thank you so much

[00:04:58.580]for your time in your evening, this evening.

[00:05:01.303]And we are coming to you

[00:05:03.100]from the three corners of the world today.

[00:05:05.260]I’m down in the South Pacific

[00:05:07.339]in New Zealand at Seequent’s headquarters.

[00:05:10.550]So you’ve got three very different times zones today.

[00:05:14.265]And wherever you’re joining us,

[00:05:16.850]it’s great to have you with us and thank you for your time.

[00:05:20.772]So let’s crack into this.

[00:05:22.880]I’ve got basically three, oh, I’ve got five main questions,

[00:05:27.769]which followed how you would approach a contaminated site

[00:05:33.370]starting with the start of a project

[00:05:36.111]right through remediation.

[00:05:38.553]But let’s think about the problem here.

[00:05:42.010]The problem, clients need experts

[00:05:45.540]to help them understand a contaminated site.

[00:05:48.985]There are stressful legal obligations

[00:05:53.420]often associated with these sites.

[00:05:56.089]Clients want to minimize the potential costs.

[00:05:59.585]They only want to spend as much as they should,

[00:06:02.404]and they want to minimize the time

[00:06:05.540]so they can move forward with this site.

[00:06:08.527]And there are other people involved,

[00:06:10.630]lots of people involved,

[00:06:12.079]stakeholders with different levels

[00:06:14.900]of technical understanding.

[00:06:16.060]There are community members, there are contractors,

[00:06:19.290]there are engineers, there are geologists,

[00:06:22.200]often corporate representatives,

[00:06:24.050]legal authorities, regulatory boards.

[00:06:27.894]You need to understand the risks for your client,

[00:06:31.318]for your communities, and for the environment.

[00:06:34.560]But more importantly, you must communicate these risks.

[00:06:39.403]Your recommendations will be based on the data you have

[00:06:42.822]and the cost benefit analysis and how you can make sure

[00:06:47.320]that clients feel confident in the plan that you present

[00:06:50.534]and make good decisions.

[00:06:53.947]Teams need to bring together

[00:06:56.300]their diverse technical experience

[00:06:58.490]and the data to bring the full picture.

[00:07:00.923]And after you make your decisions,

[00:07:03.227]do you feel you can confidently defend them with data?

[00:07:06.681]Can you show why each choice was made?

[00:07:11.163]Technology makes it easier to bring it all together,

[00:07:13.810]all your geoscience data together,

[00:07:15.981]and to tell a complete and clear story.

[00:07:18.082]And with everyone on the same page,

[00:07:20.440]you’ll gain the shared understanding and consensus

[00:07:23.440]you need to minimize time, cost, and risks.

[00:07:26.062]These are tricky sites, so many people involved,

[00:07:30.730]and potentially very legal and litigious.

[00:07:34.872]So let’s start at the start.

[00:07:36.834]And I’ll start with you, Amir.

[00:07:38.850]You’re starting out.

[00:07:39.683]There’s a whole new site.

[00:07:41.026]It’s a new project, it’s a new client.

[00:07:44.269]You might have some preliminary tests

[00:07:48.050]which are pointing to deeper contamination,

[00:07:50.570]but at this early stage of this project,

[00:07:53.540]when so much is unknown

[00:07:55.959]and so many aspects of the site

[00:07:57.870]have the potential to become very large issues,

[00:08:00.732]how do you deal with all the choices,

[00:08:02.972]all this complexity at the start?

[00:08:05.404]How do you deal with all those components?

[00:08:09.369]And what technologies are going to help you avoid the risks

[00:08:12.849]as they cascade further down into your project later on?

[00:08:16.930]Amir, what’s your response to that?

[00:08:18.993]<v Amir>Yeah, As you said,</v>

[00:08:21.084]it’s going to be a really complex problem

[00:08:25.850]that we are going to try to solve that problem.

[00:08:30.330]And starting fresh from a new project,

[00:08:34.320]we know that the problem is complex,

[00:08:36.750]but as you said, usually we don’t have enough information.

[00:08:40.530]And what we are mostly trying to do

[00:08:44.560]is collect as much information as we can

[00:08:47.920]to kind of try to make a model,

[00:08:53.050]a conceptual model in your usually brain too

[00:08:57.570]to kind of try to understand what the problem is,

[00:09:00.914]what is the complexity, what are the moving part,

[00:09:04.880]and what is it that the client wants to achieve.

[00:09:09.595]And then from that, you start to see

[00:09:15.200]that there are some gaps

[00:09:16.732]in the knowledge that you have already,

[00:09:20.440]and you try to fill those gaps with information

[00:09:24.670]that you can collect.

[00:09:27.061]Sometimes you need to go to the field

[00:09:29.440]and collect samples or do drilling to get more information.

[00:09:35.070]And then sometimes you need to talk to your client

[00:09:38.470]and understand the history of the site a little bit better

[00:09:45.070]or the other stakeholder involved.

[00:09:47.771]So then the technologies is, I think,

[00:09:50.860]the role of technologies is kind of critical

[00:09:54.791]as you try to kind of connect the dots

[00:09:58.230]and understand the relationships.

[00:10:01.860]So, as I said, a conceptual model

[00:10:05.810]is going to help you to achieve that

[00:10:09.767]which with technology can help you

[00:10:12.289]easily start from something simple.

[00:10:17.343]And sometimes by just drawing what’s going on can help you.

[00:10:24.108]And then when you collect more information

[00:10:28.070]and then you need to look at the more complex

[00:10:31.841]hydrogeological setting and the site characterization,

[00:10:36.200]then you need to somehow be able to easily

[00:10:41.239]have all of those information in a system

[00:10:45.786]to show your client or kind of collaborate

[00:10:50.610]with your colleagues and show that,

[00:10:52.650]okay, so this is what I think about the site.

[00:10:56.800]So what’s your idea?

[00:11:00.040]<v Tim>It is almost like there’s a mental model building up</v>

[00:11:04.008]in your own mind as you collect data.

[00:11:07.016]And then is that represented as the conceptual model?

[00:11:11.780]Is that the actual tangible thing

[00:11:13.650]you talk about with your client

[00:11:15.590]and other people, other stakeholders?

[00:11:17.660]<v Amir>Yeah, yeah, it start to form in your mind,</v>

[00:11:20.471]but as you move on and then you need to communicate

[00:11:23.674]that picture to your client

[00:11:26.295]and the stakeholders and other peoples involved,

[00:11:29.530]and then you need to move it from your brain

[00:11:32.810]into a piece of paper or a computer model or something,

[00:11:38.629]something like that.

[00:11:40.378]<v Tim>Right, yeah, and Tom, how do you decide</v>

[00:11:43.930]what conceptual model you’re going to need

[00:11:45.740]because there are lots of different conceptual models

[00:11:48.300]and ways to represent it, right?

[00:11:50.295]<v Tom>I think the conceptual model</v>

[00:11:53.580]will vary from site to site and problem to problem.

[00:11:57.207]Generally, you have some experience

[00:12:00.730]or know something about the situation in the area.

[00:12:04.200]You know if it’s in a glacial outwash

[00:12:07.890]or fluvial deposits or whatever.

[00:12:11.760]So you have a starting point

[00:12:15.827]and that can be either confirmed or refuted

[00:12:19.950]by the data that you can get that’s already there.

[00:12:23.959]One of the things I was wondering about is

[00:12:26.670]when you go out to these sites,

[00:12:27.580]you always at some point have to convince the customer

[00:12:33.436]whether to pay or not for additional investigations.

[00:12:38.700]And I’m wondering, Amir,

[00:12:40.660]do you find that technological advances

[00:12:43.580]make it easier to explain the problem to them

[00:12:46.740]and why you need to get more information?

[00:12:50.518]<v Amir>Yeah, I think certainly ’cause most of the time,</v>

[00:12:55.552]for example, in terms of data collection,

[00:13:02.160]for example, I need a borehole in that location.

[00:13:05.330]How you should convince the client

[00:13:08.050]that, okay, I need that borehole.

[00:13:09.820]So I think technology,

[00:13:13.622]doing some stochastic or statistical analysis on the data

[00:13:18.290]or looking at the geospatial distribution

[00:13:20.680]and the relative correlation that you have between the data,

[00:13:29.100]then you can kind of show scientifically

[00:13:32.531]and not just what you feel,

[00:13:35.590]but in terms of data, you’re looking at the data,

[00:13:38.187]and then you say, okay,

[00:13:43.139]based on the information that we have currently,

[00:13:46.230]so this is the separation, the minimum separation

[00:13:51.380]that we need between our data point.

[00:13:53.320]But if you are far beyond that,

[00:13:58.310]so then we need to take into,

[00:14:00.300]and it’s easier to communicate

[00:14:02.380]that to our clients to say, okay,

[00:14:04.002]we need to collect this information from these locations

[00:14:07.920]because science is saying so.

[00:14:13.360]And when you have a model that’s kind of tangible,

[00:14:20.320]the client can see the information and they can understand

[00:14:26.390]what you’re talking about more easily,

[00:14:28.240]and then you can kind of communicate

[00:14:29.630]all the data that you have

[00:14:31.700]in terms of geological information,

[00:14:34.107]in terms of the site itself,

[00:14:40.510]the infrastructure that you have onsite,

[00:14:43.660]and then in terms of the receptors that are close by,

[00:14:46.560]then it’s way easier to communicate that to our clients

[00:14:50.890]and to convince that they need to pay basically

[00:14:55.022]to collect those data.

[00:14:57.505]<v Tom>I wish when I had been doing consulting,</v>

[00:14:59.446]we had some holes that we have today.

[00:15:03.256]It’s being able to give them a picture of everything

[00:15:05.650]and so that they can get context and stuff.

[00:15:07.920]It’s really a game changer, I think.

[00:15:12.780]<v Amir>Yeah, for sure, yeah.</v>

[00:15:15.269]<v Tim>And with so much is unknown</v>

[00:15:17.560]at those early stages of a project

[00:15:19.260]when you’re not sure of the pathways

[00:15:21.300]and just how things are,

[00:15:26.620]how do you talk to your client when you’re uncertain

[00:15:31.900]and you’re trying to figure things out

[00:15:33.980]and they just want a cost

[00:15:35.860]and to know how this project is going to run?

[00:15:40.888]<v Amir>Yeah, I think, so what I believe</v>

[00:15:44.540]is that the uncertainty in every step of the decision-making

[00:15:52.264]needs to be communicated to the client clearly.

[00:15:56.340]And then if we can, so we can kind of characterize

[00:16:02.580]that uncertainty to our client.

[00:16:09.985]I think it’s the way to go to look at the error bar and say,

[00:16:15.150]okay, this is what we think is going on.

[00:16:18.700]This is probably the most probable picture,

[00:16:22.410]but there’s also this error bar

[00:16:25.860]or this uncertainty associated with what we think.

[00:16:29.490]And this also may not be correct

[00:16:31.750]because that might be another scenario

[00:16:34.440]that we are not aware of.

[00:16:35.650]Or based on the data that you currently have,

[00:16:39.770]so this is the most probable,

[00:16:41.870]but at the same time so we can see

[00:16:45.070]that this also might be happening with less probability.

[00:16:49.400]So if we can characterize that probability

[00:16:52.000]and show that to the client,

[00:16:53.170]I think it’s way easier later on down the road

[00:16:59.860]in the project to kind of change the path

[00:17:06.673]and kind of the client is mentally ready

[00:17:11.470]for you to say that, okay,

[00:17:14.150]that’s all of our conceptual model is now changed

[00:17:19.760]because of the one data point that we collected,

[00:17:22.630]and we need to do more investigation

[00:17:24.500]because there is another scenario now on the table

[00:17:28.080]that we need to investigate.

[00:17:30.716]<v Tim>Right, so expressing those scenarios early,</v>

[00:17:34.210]expressing uncertainty early,

[00:17:36.256]and making that really clear with the client

[00:17:39.410]sounds like that goes a long way.

[00:17:41.750]I want to ask the second question here,

[00:17:45.603]second main question as we click down through

[00:17:48.320]from a new project down to for remediation.

[00:17:53.026]So it’s time to make decisions or you want to make decisions

[00:17:58.630]about how to remediate or how to deal with the site,

[00:18:02.476]but we need to accurately delimit the plumes,

[00:18:07.200]let’s say, in the ground.

[00:18:08.620]So it’s time to build a model.

[00:18:10.626]And how are we going to do that?

[00:18:12.360]What sort of techniques are we going to lean on

[00:18:14.440]to be able to make a useful model

[00:18:18.018]of a contaminant plume in the ground?

[00:18:20.300]And I might start with you, Tom.

[00:18:22.332]What are the techniques and technologies

[00:18:26.470]you’re going to rest on for that?

[00:18:31.890]<v Tom>It depends then on the scale of the problem.</v>

[00:18:34.120]Generally I would start by using

[00:18:37.460]some kind of statistical analysis,

[00:18:39.103]do a geostatistical estimate.

[00:18:41.950]And I would also make sure

[00:18:43.870]that I would look at the hydrostratigraphy

[00:18:47.030]because that can really control how the plume develops,

[00:18:51.180]if it’s a wide plume or a long narrow plume.

[00:18:54.288]And ’cause in the beginning, as Amir was saying,

[00:18:57.760]so you don’t always have a lot of data.

[00:19:00.106]You just have really a number of limited points,

[00:19:03.200]and you can bring in other information

[00:19:05.370]like hydraulic gradients and stuff like that

[00:19:08.823]that can also maybe help there and things.

[00:19:13.003]And if you’re going to move on and do

[00:19:16.417]like flow modeling and stuff like that,

[00:19:18.650]it depends a lot again on the risk

[00:19:20.590]and the kind of receptors you have.

[00:19:24.440]But I generally start it

[00:19:25.990]with a geostatistical analysis of the data.

[00:19:29.350]It also tells you a lot about

[00:19:31.256]the weakness of the data and things like that.

[00:19:37.096]<v Tim>And, Amir,</v>

[00:19:39.260]you love a geostatistical approach as well.

[00:19:41.314]Tell us more about how you go about this stage.

[00:19:45.770]<v Amir>Yeah, as Tom mentioned,</v>

[00:19:47.277]it’s just the geostatistical is a necessity.

[00:19:51.693]So I think that delineation of the plume

[00:19:56.109]and founding a boundary

[00:19:59.434]based on the knowledge that you have is critical.

[00:20:08.781]I can’t say that accurately because it’s really hard

[00:20:13.480]in the geological context to be accurate,

[00:20:20.020]but we try our best to come up

[00:20:24.720]with the most probable picture

[00:20:26.900]based on the information that we have.

[00:20:29.154]And then sometimes it’s based

[00:20:31.950]on the complexity of the problem.

[00:20:34.594]I think it’s necessary to go that additional step

[00:20:38.020]of trying to characterize the uncertainty

[00:20:41.077]associated with that estimation,

[00:20:44.439]and then come up with some representation,

[00:20:49.760]and then, okay, this is the volume of the plume

[00:20:54.510]or the extent of the plume that’s most probable,

[00:20:57.800]but also these other scenarios are possible,

[00:21:01.680]so we can be wrong basically by twice the size of the plume.

[00:21:07.200]But I think we need to communicate that to our client

[00:21:14.312]and make them understand the risk

[00:21:16.890]associated with the uncertainty,

[00:21:19.456]and if it’s possible, convince them to reduce that risk

[00:21:26.173]as much as they can.

[00:21:28.120]So by collecting more information,

[00:21:30.507]sometimes that’s possible to reduce that risk.

[00:21:34.880]And show that, okay, this error bar

[00:21:37.547]based on the information that you have

[00:21:39.381]is now it’s that big.

[00:21:43.413]But if you collect these samples,

[00:21:45.568]then it’s going to bring that error bar

[00:21:49.310]a little bit lower or a lot lower,

[00:21:52.330]then that’s going to save you down the road.

[00:21:56.725]And then after that, when the plume is characterized,

[00:22:01.280]then we can move on to the numerical modeling.

[00:22:04.427]As Tom mentioned,

[00:22:05.800]it really depends on the risk to the receptor.

[00:22:08.420]If you want to say, okay, so how long or how many years

[00:22:12.900]it’s going to take for this plume to go

[00:22:16.027]from this current condition

[00:22:18.520]and with what concentration

[00:22:21.130]it’s going to reach to that receptor?

[00:22:23.599]Then those question can be answered

[00:22:26.700]using the numerical models and flow and transport models.

[00:22:32.469]<v Tim>Is it a case of matching up</v>

[00:22:35.331]the tools in your toolbox

[00:22:37.100]to the complexity and the uncertainty

[00:22:38.916]that’s associated with the site

[00:22:40.830]and using the appropriate tool

[00:22:43.000]for the appropriate conditions?

[00:22:45.490]<v Amir>Yeah, certainly.</v>

[00:22:47.908]Sometimes the problem is not that complex

[00:22:53.604]when you’re not having a lot of heterogeneity in the system

[00:22:58.200]or the contamination or the species of the contamination

[00:23:04.630]is not that complex,

[00:23:07.938]then we can say that, okay, use data on it.

[00:23:11.538]So geostatistical tool can also

[00:23:13.991]kind of provide an answer for us.

[00:23:16.728]Looking at the historical data collected,

[00:23:21.153]we can also move toward

[00:23:23.930]from just looking at the spatial geostatistic,

[00:23:26.870]you can use special temporal geostatistic

[00:23:31.690]and look at how the plume has evolved.

[00:23:35.297]If you have information and you do have in some site,

[00:23:38.710]you have some historical information that you can utilize,

[00:23:42.019]and based on that, it can give you an idea, okay,

[00:23:47.550]so this is the information that I have currently

[00:23:52.410]is going to be enough for me to make decision

[00:23:55.486]and move forward with the site

[00:23:58.470]or do I need to collect more samples

[00:24:01.610]and answer some of the key questions

[00:24:05.965]that’s not been answered yet?

[00:24:09.528]<v Tim>Right, what sort of tools</v>

[00:24:12.680]would you have in your toolbox, Amir?

[00:24:14.600]And I’ll ask you as well, Tom.

[00:24:18.570]And what are your go-to approaches for this phase?

[00:24:25.571]<v Amir>Yeah, I think we should always start simple</v>

[00:24:33.190]and then make things complex as needed.

[00:24:36.870]So complexity always is not the solution.

[00:24:42.701]But it can be starting from a simple 2D map

[00:24:47.179]and then some cross sections of the site.

[00:24:51.240]And then if you need it, if you have a lot of information,

[00:24:54.922]a lot of historical data, then you need more,

[00:24:58.829]something more robust.

[00:25:00.630]Then you need to look at all the angles of the problem.

[00:25:03.719]And the 3D tool definitely is going to be helpful.

[00:25:07.476]And then as get things more complex,

[00:25:12.260]than you need to have statistical tools available,

[00:25:15.520]geostatistical tools.

[00:25:16.770]And then for the plume characterization,

[00:25:22.290]sometimes you need to go through that

[00:25:24.165]special temporal geostatistics to answer your question.

[00:25:29.609]Yeah, it’s that level of complexity

[00:25:32.840]really depends on the site and the problem

[00:25:35.368]that you’re trying to solve.

[00:25:38.438]<v Tim>And Tom, what sort of tools</v>

[00:25:41.010]for modeling plumes would you have?

[00:25:44.168]What are your technologies?

[00:25:45.850]<v Tom>In a lot of ways it’s really similar</v>

[00:25:48.210]to what Amir was saying,

[00:25:49.081]though, I mean, I’m slightly biased.

[00:25:51.160]I do work for Seequent so–

[00:25:52.757](Tim laughs)

[00:25:53.840]And I’ve been building 3D tools

[00:25:55.650]even before I started working for Seequent.

[00:25:58.050]So I’ve always liked getting things in 3D.

[00:26:02.368]It’s also maybe ’cause of the way I think.

[00:26:05.010]But I always really like getting

[00:26:07.890]all the data and everything in a 3D where,

[00:26:11.860]it’s like I’ve seen plume starched my sewer lines and stuff

[00:26:16.150]where they poured stuff from the sewer

[00:26:17.740]and there was holes and stuff.

[00:26:19.080]And so by getting everything

[00:26:20.740]that you might have around the site into the model,

[00:26:24.971]I’ve always just found it gives me

[00:26:27.090]a better understanding of the problem

[00:26:29.930]and makes it easier to explain.

[00:26:33.314]But certainly the fewer data you have,

[00:26:37.816]the less robust geostatistical

[00:26:40.866]and other statistical analysis you can do, right?

[00:26:44.063]And you don’t want to over-complicate the problem

[00:26:47.340]in the beginning.

[00:26:48.380]So it’s to weigh the techniques as you move forward.

[00:26:54.190]And certainly time series analysis

[00:26:57.271]if you have that kind of data available

[00:26:59.804]is really valuable ’cause it gives you an idea

[00:27:02.500]of how things are evolving, how fast things are evolving,

[00:27:06.150]and that affects the critical nature of the problem.

[00:27:11.240]If things are moving faster,

[00:27:12.400]you need to maybe be more reactive,

[00:27:14.810]and it could be of a greater risk for your customer.

[00:27:19.291]<v Tim>Yeah, time series analysis,</v>

[00:27:21.630]I guess that’s empirical information

[00:27:23.960]on just what has been happening through time.

[00:27:26.537]And that’s really valuable to understand how.

[00:27:30.350]Hey, let’s move on.
<v ->How things are evolving.</v>

[00:27:32.660]<v Tim>Yeah, how things are evolving.</v>

[00:27:34.220]Let’s go to the next phase.

[00:27:36.260]Let’s say it’s time to design a program

[00:27:38.890]to deal with the site.

[00:27:41.210]So you’ve started, you’ve collected a lot of data,

[00:27:44.050]you’ve made conceptual models,

[00:27:46.270]you’ve dealt with a lot of the complexity

[00:27:49.670]and the uncertainty in these models,

[00:27:51.310]but we want a program to deal with the site.

[00:27:55.097]And so maybe it’s as simple as removing the source

[00:27:58.380]and then just monitoring it,

[00:27:59.450]or maybe you need to dig it,

[00:28:02.040]or you need to pump it or heat treat it,

[00:28:04.226]heat treat it or transform it.

[00:28:07.917]Each of these are going to have

[00:28:09.360]their own impacts, their own costs,

[00:28:13.160]and it’s all going to depend on the type of contaminated site.

[00:28:17.390]What’s your approach?

[00:28:18.610]What’s your general approach to this,

[00:28:20.960]making a decision in this space, Amir?

[00:28:24.530]How do you deal with your clients?

[00:28:26.760]How do you communicate?

[00:28:29.737]<v Amir>Yeah, as you said,</v>

[00:28:30.867]most of those remediation techniques

[00:28:33.490]are contaminate kind of dependent.

[00:28:37.340]So if you were dealing with a NAPL,

[00:28:39.690]so then you have different remediation technique

[00:28:44.390]than when you’re dealing with salts.

[00:28:48.683]So it’s just some of that it’s based on that consideration.

[00:28:55.150]And then the other part is going to be,

[00:28:57.840]so when you have different options,

[00:28:59.290]as you mentioned earlier,

[00:29:01.030]so it’s always a cost benefit analysis.

[00:29:07.420]So we usually come up

[00:29:09.953]with a couple of different remediation scenarios,

[00:29:14.363]and then we can test those remediation scenarios

[00:29:19.300]usually by conducting numerical modeling.

[00:29:22.970]So then you can look at how much of the contamination,

[00:29:28.140]the contaminants that you can remove

[00:29:30.000]and then how much probably is going to remain in place,

[00:29:33.030]and what’s the cost associated with all of those activities,

[00:29:36.260]and at the end, present and look at

[00:29:40.030]all of the costs and the benefits

[00:29:42.530]that that remediation is going to provide,

[00:29:45.090]and then make decision

[00:29:46.960]based on that cost benefit analysis, yeah.

[00:29:53.210]<v ->But there’ll be other factors, weren’t there, Tom?</v>

[00:29:56.360]Not just cost benefit,

[00:29:58.290]but there are the different parties that are involved.

[00:30:01.870]There are different stakeholders here,

[00:30:03.500]there’s client, there’s communities.

[00:30:06.140]How do you communicate that?

[00:30:07.831]How do you get to a decision in the space?

[00:30:12.051]<v Tom>For me, it’s about explaining</v>

[00:30:16.540]the rationale behind the approach, right?

[00:30:20.756]Generally there’s like what Amir was saying,

[00:30:24.290]again there’s receptors.

[00:30:25.790]It depends on the use and where the plume is going

[00:30:28.640]and those kind of things.

[00:30:30.760]So it’s the risk that it poses,

[00:30:33.850]and explain that clearly to all the different stakeholders.

[00:30:39.198]It’s really, really hard, if not impossible,

[00:30:42.990]to completely clean up a site.

[00:30:44.412]There’s always going to be some remedial something,

[00:30:50.257]pollution left behind.

[00:30:52.839]And you have to explain that it’s not possible.

[00:30:57.319]And also how deep the plume is, for example,

[00:31:00.670]also eliminates certain techniques.

[00:31:02.256]If it’s really deep, you’re not going to dig it up, right?

[00:31:06.871]And other techniques that may give you a better remediation

[00:31:10.320]could cause other problems, right,

[00:31:12.951]because they may cause settlement

[00:31:14.870]in surrounding buildings or something like that.

[00:31:18.311]So it’s just basically telling the story.

[00:31:22.430]You have to explain as clearly as possible

[00:31:25.588]why you’ve come to this solution

[00:31:27.220]and that it is the best solution based on cost

[00:31:30.330]and based on everybody’s general interest

[00:31:34.047]around the problem.

[00:31:36.373]In my experience,

[00:31:37.380]most people don’t want to leave an inclusion behind, right?

[00:31:39.902]They want to clean it up.

[00:31:44.021]<v Amir>Yeah, yeah.</v>

[00:31:44.854]<v Tim>Amir, you go ahead, mate, yeah.</v>

[00:31:47.585]<v Amir>No, go ahead.</v>

[00:31:49.150]<v Tim>I was going to ask do your clients struggle</v>

[00:31:51.646]to make a decision when they’re presented with scenarios

[00:31:54.500]and options for remediation?

[00:31:56.290]Is it hard for them because they’re not

<v ->It really depends</v>

[00:31:59.554]on the costs.

[00:32:00.387]So if it costs this.
<v ->Right.</v>

[00:32:02.100](Tim and Tom laughing)

[00:32:05.210]<v ->Let’s say you’ve chosen or the client has chosen</v>

[00:32:09.650]a remediation strategy,

[00:32:11.150]and your remediation is in full swing now,

[00:32:13.540]so maybe you’re pumping or maybe you’re heat treating

[00:32:17.340]or doing something like that,

[00:32:18.650]but you’re operating to remediate.

[00:32:22.109]What are some of the best ways that you can monitor?

[00:32:25.049]Because this is going to take some time typically.

[00:32:27.976]How are you going to monitor and sample

[00:32:31.299]and report on that remediation?

[00:32:34.864]And how are you going to have confidence

[00:32:37.860]or relay your confidence that your technique is working?

[00:32:42.100]How are you going to communicate that with your client?

[00:32:45.288]<v Amir>Yeah, again that mapping</v>

[00:32:47.970]kind of help us to do that.

[00:32:50.180]So when at remediation,

[00:32:55.590]the site is under remediation,

[00:32:57.920]and then you know that some information

[00:33:01.864]kind of get collected regularly at the site,

[00:33:04.570]and then you have that kind of opportunity

[00:33:11.610]to look at those information

[00:33:13.170]and try to relate that to the remediation

[00:33:18.564]that’s ongoing at the site

[00:33:20.690]and try to see if that remediation technique

[00:33:26.022]that’s already in place is effective

[00:33:29.500]or how effective that remediation is going to be.

[00:33:33.010]Is that the rate of, extraction rate

[00:33:36.810]is kind of reaching to a steady state condition

[00:33:41.480]or kind of what’s that rate of change

[00:33:48.210]when you’re dealing with LNAPL also.

[00:33:50.867]So are you extracting, reaching to that point

[00:33:55.590]that your remediation technique is no longer effective

[00:33:59.900]and you’re better off moving

[00:34:02.310]to another remediation technique

[00:34:04.416]or you just simply stay and watch and monitor the situation

[00:34:10.020]rather than doing anything?

[00:34:12.160]So those kind of decisions is hard

[00:34:18.190]and it really depends on the data that’s been collected.

[00:34:22.933]Sometimes because you have the remediation system working,

[00:34:27.450]so you also add another level of complexity to the site,

[00:34:31.209]so that the dynamic and the impact

[00:34:34.904]of the remediation system itself,

[00:34:38.970]so add a level of complexity or noise

[00:34:42.120]to the data that’s been collected.

[00:34:44.582]And you need to understand that noise

[00:34:47.590]and try to remove that noise from the data,

[00:34:51.206]and then make decision based on the actual information,

[00:34:56.530]not based on the noise that’s been kind of

[00:35:00.610]forced into your datasets.

[00:35:02.390]So those are important things that we need to consider.

[00:35:09.510]<v Tim>Right, so it’s a dynamic system</v>

[00:35:12.049]where the actual remediation techniques

[00:35:14.340]are changing the data.

[00:35:16.410]You’re not seeing the system in its natural state anymore.

[00:35:20.209]Very difficult.

[00:35:21.280]And Tom, how are you going to communicate with your client?

[00:35:27.836]I mean that you could email, you could phone call,

[00:35:30.620]but it’s 2020.

[00:35:32.609]What are some of the advanced ways

[00:35:35.926]that you can really make this easy

[00:35:38.160]for the client to understand as the remediation runs?

[00:35:43.290]<v Tom>I don’t know if any of those</v>

[00:35:45.080]are ever easy to understand,

[00:35:47.100]but one thing just to follow up on Amir is saying

[00:35:53.860]is one thing that I’ve done sometimes

[00:35:55.820]is actually do model scenarios

[00:35:58.209]with or without the remediation

[00:36:00.300]so that you maybe you can find how much noise there is,

[00:36:03.707]and then you can use those two different scenarios

[00:36:06.480]to explain to the customer

[00:36:08.153]what it would be if you hadn’t done the remediation,

[00:36:10.853]this is the benefit that you’re getting from a remediation.

[00:36:15.213]Those sites usually require that you had really good data

[00:36:18.700]before you start remediating.

[00:36:22.010]But, like I was saying in the beginning,

[00:36:27.094]a lot of times it’s a good picture, right?

[00:36:31.550]It’s all about being able to show them visually

[00:36:36.214]how things have changed.

[00:36:37.970]And if you can show them where,

[00:36:41.300]say, a pumping well, is for capturing a plume,

[00:36:44.870]and show how the plume has changed

[00:36:46.930]since that has been in operation and things like that,

[00:36:49.792]it just makes it much easier.

[00:36:54.260]Also if you were doing a funnel and gate

[00:36:56.290]and other kinds of remediation strategies,

[00:37:00.608]being able to show it in 3D

[00:37:02.760]and how things are changing around that and context,

[00:37:06.240]’cause I think that’s a lot of times

[00:37:07.470]where they have trouble.

[00:37:08.470]My experience is if you just show them that,

[00:37:10.667]they can’t picture

[00:37:11.820]that it’s a 3D compression of things, right?

[00:37:14.452]And then maybe the plume is constrained

[00:37:17.886]by a specific gravel layer or something like that.

[00:37:21.194]And again that’s where combining things

[00:37:23.903]in a 3D interactive environment can be useful.

[00:37:30.516]<v Amir>Yeah, certainly, yep.</v>

[00:37:33.470]<v Tim>Yeah, and what are some of the creative ways</v>

[00:37:36.740]you’ve reported back during remediation, Amir?

[00:37:40.794]What’s your go-to for that kind of communication?

[00:37:47.466]<v Amir>Yeah, I think that the important part</v>

[00:37:51.020]is we need to acknowledge, as I said before,

[00:37:53.910]so I’m really a fan of characterizing uncertainty

[00:37:58.906]and just considering that impact

[00:38:01.980]on every aspect of your project.

[00:38:06.071]So I think that that’s going to be really be helpful

[00:38:09.269]for the client to understand how things are evolving,

[00:38:13.120]because sometimes when you look at the raw data,

[00:38:16.320]and then even if you map

[00:38:18.280]based on the information that you have,

[00:38:21.244]so you’re not looking at all the variables

[00:38:25.680]that you don’t know.

[00:38:26.513]So the porosity, the bulk density,

[00:38:30.876]all of those variables, the hydraulic conductivity,

[00:38:33.650]all of those variables or even the characterization

[00:38:37.686]of the plume itself is complex,

[00:38:42.758]and it has a lot of unknown or estimated variables in it.

[00:38:48.694]So I think that characterizing that,

[00:38:51.506]it’s going to help the client to understand

[00:38:55.115]that, okay, so we think that things are going down,

[00:39:00.200]so the concentrations,

[00:39:01.510]but there’s also a possibility that we might be wrong

[00:39:04.570]because these factors are involved.

[00:39:09.116]So then it’s going to help to acknowledge

[00:39:13.140]that all of those unknown in the equation,

[00:39:15.890]that we know that that’s also a possibility, so, yeah.

[00:39:22.020]<v Tim>And do you do that using simulation?</v>

[00:39:24.539]I mean, like stochastic simulation?

[00:39:26.757]<v Amir>Yeah, so you can do it</v>

[00:39:29.104]doing a stochastic simulation.

[00:39:32.688]Sometimes that’s the way to go.

[00:39:35.069]Sometimes even looking at a simple Monte Carlo analysis,

[00:39:41.410]just looking at the probability of your input parameters

[00:39:45.360]and then try to sample that probability of space

[00:39:48.310]and kind of map it based on that probability of space,

[00:39:53.110]and then that’s the way to go.

[00:39:55.431]So it really depends on the problem.

[00:39:58.592]Then that’s going to be easier to understand

[00:40:02.870]the complexity for the client

[00:40:05.260]and then kind of acknowledge the unknown in the equation.

[00:40:09.107]Yeah, so and then, okay,

[00:40:10.843]so if we can have a better understanding,

[00:40:13.090]and then we can look at the sensitivity

[00:40:15.250]of all of those parameters,

[00:40:17.000]and say, okay, if we have a better understanding,

[00:40:19.326]for example, about the bulk density or about the porosity,

[00:40:22.990]then that error bar actually

[00:40:25.590]is going to be way smaller than it is right now.

[00:40:28.030]So then we can kind of understand

[00:40:31.190]which direction of sample collection do we need to go

[00:40:34.089]to reduce the uncertainty.

[00:40:42.280]<v Tim>Nice, so some really advanced techniques there.</v>

[00:40:45.020]We’re right at the end of our project now.

[00:40:46.710]You might have finished your remediation,

[00:40:49.380]you’ve monitored it through,

[00:40:50.970]and you have confidence that the job has been done,

[00:40:55.499]but some sites are still problematic.

[00:40:58.806]There’s a residual contamination

[00:41:01.960]or there’s other unforeseen effects

[00:41:05.280]that have happened there.

[00:41:06.270]So in your experience, how do you leave a project

[00:41:12.650]and what’s the strategy

[00:41:15.764]to deal with any of these unforeseen effects?

[00:41:20.329]So, Amir, what sort of problematic effects

[00:41:24.337]do you see in these sorts of sites

[00:41:27.830]and what’s been your experience?

[00:41:32.553]<v Amir>Yeah, there’s always problems</v>

[00:41:36.980]that need to be solved.

[00:41:38.090]So, as Tom mentioned,

[00:41:39.663]I think that we can’t really clean up 100%.

[00:41:44.660]So it’s really hard or if it’s impossible.

[00:41:53.900]I think looking at the problem

[00:41:54.907]and then trying to clearly communicate that to our client

[00:41:59.270]and show that the risk of, for example,

[00:42:04.057]the residual contamination is minimal

[00:42:07.930]or that can be mitigated

[00:42:11.796]by having a monitoring network in place,

[00:42:17.980]and then looking at how that residual

[00:42:20.490]is evolving through time.

[00:42:22.825]And even sometimes it’s just the site is still active,

[00:42:30.491]then even the client has no idea

[00:42:34.330]if the source is contained or not.

[00:42:37.364]So then you were conducting that remediation activity,

[00:42:41.030]then you don’t know if dirty stuff

[00:42:47.900]is leaking in the ground or not.

[00:42:49.610]So then you need to have

[00:42:52.040]some sort of contingency plan in place

[00:42:55.151]to make sure to cover that part for the client, yeah.

[00:43:06.752]<v Tim>Tom, what’s been your experience</v>

[00:43:09.130]with problematic sites?

[00:43:18.010]<v Tom>I can’t think of any problem site</v>

[00:43:20.070]that wasn’t problematic,

[00:43:21.110]but I think that the biggest problem

[00:43:25.840]is explaining to people that what’s left

[00:43:29.459]and the monitoring plan,

[00:43:34.320]to watch it is satisfactory,

[00:43:40.247]because, as Amir’s pointed out,

[00:43:43.090]there’s always uncertainty, right?

[00:43:45.450]So a monitoring well could miss something, right?

[00:43:49.370]But to demonstrate to people that this is good enough,

[00:43:52.699]and you will detect something before there is a problem

[00:43:57.440]that threatens their interest

[00:43:59.490]for the different stakeholders.

[00:44:01.979]And the other problems that I’ve often seen is that

[00:44:05.830]the ideal solution isn’t feasible for some reason,

[00:44:11.532]because of how people want to use the site

[00:44:15.760]or various other stakeholder interests,

[00:44:18.740]that it’s always a compromise,

[00:44:21.290]and getting a compromise that has an acceptable risk

[00:44:24.610]can be, right, at times challenging.

[00:44:32.984]<v Tim>Complex sites, you can’t see everything.</v>

[00:44:35.886]You’ve got to rely on your data,

[00:44:38.280]and that’s the nub of it I think.

[00:44:42.380]You just cannot see what you’re dealing with.

[00:44:44.526]So thank you for answering those questions, Tom, Amir.

[00:44:50.162]I’m just looking at my watch.

[00:44:51.370]We still got 15 minutes and I’m going to turn it over

[00:44:54.070]to our audience questions.

[00:44:56.560]Thank you for that person.

[00:44:57.750]I’ve got one here.

[00:44:59.168]And here we go.

[00:45:00.852]3D plumes are typically interpolated from sample data

[00:45:05.950]and then constrained by geology,

[00:45:07.935]but oftentimes they do not incorporate groundwater flow.

[00:45:12.010]So do you have any thoughts on this?

[00:45:14.350]And maybe we’ll start with your Tom.

[00:45:15.540]Do you have any thoughts?

[00:45:16.799]Would a transport model be a more reliable estimate

[00:45:22.543]since that incorporates eviction

[00:45:25.640]of other transport processes?

[00:45:27.804]What are your thoughts, Tom?

[00:45:28.960]I’ll come to you next, Amir.

[00:45:31.214]<v Tom>Technically yes, but sometimes you know so little</v>

[00:45:35.490]that the added value is questionable.

[00:45:41.892]Obviously a flow and transport model incorporates

[00:45:47.310]a lot of processes that you can actually include things

[00:45:52.090]like the groundwater table gradient in an interpolation

[00:45:56.130]if you want, right?

[00:45:57.508]There are ways to do that.

[00:46:02.400]One thing I would say is that I would actually do

[00:46:08.160]what he suggested, meaning, the other way around

[00:46:10.580]is I would constrain the samples

[00:46:13.810]by the different geological formations

[00:46:17.070]and how they transport water,

[00:46:19.050]say, a sand and gravel are different than, say, a silt,

[00:46:22.392]and then look at the problem,

[00:46:26.193]because otherwise you’re comparing apples and oranges.

[00:46:33.606]<v Tim>Amir, your thoughts.</v>

[00:46:35.408]<v Amir>Yeah, as Tom mentioned,</v>

[00:46:37.640]so when you have information

[00:46:41.370]about the geology constraint and also the water table,

[00:46:45.431]there are ways that you can use

[00:46:48.100]and utilize those information

[00:46:50.872]to kind of help you characterize and delineate

[00:46:55.480]your plume more effectively or more realistically.

[00:47:00.200]So, for example, you can look at, again,

[00:47:04.416]if in some certain conditions that that hydraulic gradient,

[00:47:10.710]it’s going to kind of match up

[00:47:12.870]with where your plume is moving towards,

[00:47:15.880]so then you’re anisotropy factor in interpolation,

[00:47:20.810]it can be aligned with that anisotropy direction

[00:47:24.638]that you have based on the water table,

[00:47:27.584]for example, orientation,

[00:47:29.300]then that’s going to help you in your estimation as well.

[00:47:33.728]And then if you have information

[00:47:36.440]about the geological difference

[00:47:41.770]in the system that you are studying,

[00:47:44.090]the data collected in those geological units

[00:47:49.429]then can help you to kind of have that

[00:47:52.700]instead of having just one model interpretation,

[00:47:57.170]then you have kind of a modular interpretation.

[00:48:00.230]And kind of seeing the effect

[00:48:03.700]of that non-stationarity in the system,

[00:48:05.820]so you have, for example, sandy and a coarser material,

[00:48:11.287]and then you have a finer material,

[00:48:13.860]then you knew that plume is not going to travel

[00:48:17.250]in these two at same rate,

[00:48:19.940]then if the data collected in those two units,

[00:48:26.890]then you can use that in your favor and use those separately

[00:48:30.480]to characterize and use it in different statistical

[00:48:34.510]or geostatistical approach to kind of modulate the main

[00:48:38.720]into two different modules and then re-interpolate it,

[00:48:41.880]and then kind of combine those information

[00:48:45.400]so that there are ways to handle those issues.

[00:48:49.620]And then regarding the numerical model,

[00:48:51.880]so for numerical model,

[00:48:54.830]you need to establish your initial condition,

[00:48:58.584]which the only way that you can establish

[00:49:01.910]is mapping your plume,

[00:49:04.554]which is you need to start with the geological

[00:49:11.070]or interpolation of your plume,

[00:49:13.100]and then move on to a numerical model

[00:49:15.530]to try to assess the risk to your result, yeah.

[00:49:24.417]<v Tom>I think it’s also important</v>

[00:49:25.761]to remember what kind of plume it is too, right?

[00:49:28.240]If it’s a DNAPL,

[00:49:29.510]it’s going to be a completely different problem

[00:49:31.100]than if you’ve got a salt

[00:49:31.969]or something that’s easily dissolvable in water too.

[00:49:36.873]<v Amir>Yeah, yeah.</v>

[00:49:38.227]<v Tom>They’re really important.</v>

[00:49:39.990]<v Amir>Yeah, that’s going to, that’s LNAPL DNAPL.</v>

[00:49:42.507]And then if you’re looking at the aqueous phase,

[00:49:45.450]or you’re looking at the oil phase,

[00:49:50.760]so then it’s completely, or non-aqueous phase,

[00:49:54.910]then it’s going to be a completely different problem

[00:49:57.367]and different tool that you need to utilize

[00:49:59.440]and different considerations for sure.

[00:50:02.029]<v Tim>Yeah, you got to know</v>

[00:50:02.911]what you’re dealing with for sure.

[00:50:05.070]And I guess experience comes to play there.

[00:50:08.063]Hey, I’ve got another question here.

[00:50:09.812]This one’s about geostats and lag spacing.

[00:50:13.424]So unlike exploration geostats,

[00:50:17.498]I guess in the mining sector maybe,

[00:50:20.528]wells often are variably spaced.

[00:50:24.048]So what is your method

[00:50:25.740]for determining a reasonable lag spacing

[00:50:28.160]when your wells are variably spaced

[00:50:31.150]in a contaminated site, Amir?

[00:50:34.930]<v Amir>Yeah, I think it’s a benefit</v>

[00:50:37.616]of having variably spaced.

[00:50:40.790]It’s not a negative thing I think.

[00:50:44.294]Based on my geostatistical experience,

[00:50:47.320]I think that’s kind of a benefit

[00:50:49.200]of having that variably spaced,

[00:50:51.740]so then when you’re looking at your variogram

[00:50:55.250]and doing that variography,

[00:50:57.798]then you have all sorts of variation

[00:51:00.464]in your basically lags operations,

[00:51:04.870]and then you can change the tolerance to kind of cover

[00:51:08.410]and have different points and nodes representing,

[00:51:11.960]and then you can come up with a better understanding

[00:51:14.630]about the covariance function.

[00:51:17.427]So I don’t see that as a negative thing.

[00:51:20.904]So the issue usually is that you have limited data.

[00:51:26.650]So, and then the interpretation

[00:51:30.550]and having that limited information

[00:51:35.476]kind of limit our understanding to characterize the variogram

[00:51:41.939]in a way that it needs to be characterized.

[00:51:48.440]So we need to kind of, when we have that kind of situation,

[00:51:52.390]I think we need to also consider

[00:51:54.710]the uncertainty in the variogram

[00:51:58.757]as one of the other unknown in that equation.

[00:52:03.240]So then you need to try to characterize

[00:52:05.660]that uncertainty in the variogram as well

[00:52:08.414]when you’re interpreting the plume.

[00:52:14.477]<v Tom>But also if you know some characteristics</v>

[00:52:18.410]or general characteristics of the system,

[00:52:20.801]the groundwater table gradient,

[00:52:22.428]the hydraulic conductivity,

[00:52:24.120]and some crude thoughts about the size of the plume,

[00:52:29.649]then there are techniques for designing a lag spacing,

[00:52:34.236]the sample spacing,

[00:52:35.943]so that it’ll better characterize your plume.

[00:52:41.070]But, like Amir was saying,

[00:52:43.174]my experience is that you usually run out of money

[00:52:46.260]before you (laughs) can get a really good standpoint.

[00:52:54.210]But again the variable, just to reinforce what he said,

[00:52:56.636]the variable spacing is a good thing.

[00:52:58.600]It’s not a bad thing.

[00:53:00.327]And if you look at any classical

[00:53:02.990]geostatistical sampling design,

[00:53:05.880]it says to make sure you have variable spacing.

[00:53:10.375]<v Tim>It’s that cost benefit again, isn’t it?</v>

[00:53:12.920]It’s all down to cost.

[00:53:14.175]Hey, you were talking before, Amir, you were talking about

[00:53:18.073]geostatistical simulation techniques and Monte Carlo,

[00:53:21.867]and I’m going to go out there on a limb and say and propose

[00:53:25.580]that maybe not all environmental geoscientists like yourself

[00:53:31.810]use those sorts of techniques.

[00:53:33.160]So if there’s someone in the audience

[00:53:34.560]who is interested in starting,

[00:53:37.583]is there a place that you would advise

[00:53:40.400]that they get going in the space?

[00:53:43.663]Maybe just one more simple technique.

[00:53:46.040]And how could they apply geostat simulation

[00:53:50.020]to one of the problems?

[00:53:52.150]You’ve got any advice where someone might start?

[00:53:56.772]<v Amir>Yeah, I think</v>

[00:53:59.642]the geostatistical simulation in general,

[00:54:02.460]it’s a really complex, I think, science.

[00:54:06.084]It’s been evolving

[00:54:09.123]into then some really complex technique

[00:54:12.120]to characterize heterogeneity.

[00:54:13.423]It’s been developed during the past maybe 20, 30 years,

[00:54:19.557]but at the same time so the technique that usually

[00:54:23.503]there’s just a geostatistical technique that we use.

[00:54:26.654]So for example, Kriging,

[00:54:29.944]it’s a complex equation mathematically,

[00:54:33.530]but it’s not complex to apply.

[00:54:36.366]But at the same time, so then you can,

[00:54:40.867]I think most of the geostatistical softwares,

[00:54:44.598]they have a portion or a part for geostatistical simulation

[00:54:51.200]based on, for example, Kriging.

[00:54:56.021]It’s the Gaussian, for example, simulation.

[00:54:59.370]So it’s based on the Kriging idea.

[00:55:02.742]And then you have that tool,

[00:55:06.140]then it’s just a matter of understanding

[00:55:09.270]some key parameters.

[00:55:11.871]And then from that, it’s not that hard to implement.

[00:55:18.720]I know it’s counterintuitive.

[00:55:23.969]<v Tim>Can it be self-taught do you think</v>

[00:55:26.100]sequential Gaussian simulation?

[00:55:27.504]Can you learn that online

[00:55:29.770]or is there somewhere you’d recommend that people go to–

[00:55:34.460]<v Amir>I think it needs a little bit of formal education.</v>

[00:55:41.040]<v ->Right.</v>
<v ->Or just sitting in a class.</v>

[00:55:43.030]That might help.

[00:55:44.530]I couldn’t find, unfortunately, lots of,

[00:55:48.683]after you pass that barrier to understanding the whole idea,

[00:55:55.191]then you can teach yourself those concept,

[00:55:59.130]but it’s just that the starting point

[00:56:02.060]and understanding the whole idea of geostatistics,

[00:56:06.446]then that’s a little bit,

[00:56:09.628]I think it needs a little bit of formal education, yeah.

[00:56:13.494]<v Tim>No, thank you for that.</v>

[00:56:15.028]Good advice there.

[00:56:16.570]Hey, we’re coming to the top of the hour,

[00:56:18.340]but we’ve just got one more question,

[00:56:20.375]and it reads like this,

[00:56:23.151]Contaminated sites,

[00:56:24.516]often contaminated sites deal with politics,

[00:56:28.186]namely only showing a plume

[00:56:31.790]where it’s been confirmed with wells correctly.

[00:56:35.257]What techniques can be used

[00:56:37.776]to keep the interpolation conservative

[00:56:40.600]and not extrapolate too far?

[00:56:43.618]Ooh, politics and plume boundaries.

[00:56:48.144]Tom, what’s your experience here?

[00:56:51.899]<v Tom>Well, I kind of alluded to that a bit before.</v>

[00:56:56.346]There’s always political constraints

[00:56:58.380]about what you can do and everything.

[00:57:02.682]And this goes back to something

[00:57:05.285]that both Amir and I have been saying a lot through this,

[00:57:08.840]and that’s that wonderful world, geostatistics.

[00:57:15.290]And it takes a lot of, in my experience,

[00:57:18.250]a lot of patience and education

[00:57:22.410]of the customers and of the regulators,

[00:57:24.870]but geostatistics has this, it’s called BLUE.

[00:57:31.290]It’s the Best Linear Unbiased Estimator, right?

[00:57:36.890]And it’s to carefully educate them

[00:57:43.820]so that they come on a journey of self-discovery,

[00:57:46.830]so that they can accept that

[00:57:51.040]these estimates are conservative.

[00:57:56.149]And another way I do that

[00:57:58.863]is also to do these simulations and stuff like that

[00:58:02.910]’cause that will also demonstrate

[00:58:05.670]how the estimate is conservative,

[00:58:09.865]’cause sometimes, I think I’m going to stop there.

[00:58:16.250]I’d like to hear what Amir has to say. (laughs)

[00:58:20.244]<v Amir>Yeah, yeah, even in geostatistics sometimes,</v>

[00:58:28.325]that extrapolation is based on the information

[00:58:32.220]that’s coming from the data.

[00:58:33.870]So it’s just the information suggesting that there is,

[00:58:38.210]for example, this branch in the data.

[00:58:41.210]So there is that’s either 100 meters of correlation,

[00:58:46.344]and then you have a data point

[00:58:48.435]and then that has a concentration.

[00:58:52.146]And then after that, you don’t have any,

[00:58:55.411]basically going back into baseline concentration.

[00:59:00.446]that data point.

[00:59:02.206]So then based on the correlation

[00:59:04.958]that exists within the data set,

[00:59:08.080]then we kind of extrapolate.

[00:59:15.006]Sometimes it seems to be a little bit too far,

[00:59:17.820]but the issue is because we don’t have information,

[00:59:21.890]so that’s why it’s educated guess

[00:59:26.850]based on the information that we collected.

[00:59:30.194]And then if you want to kind of say, okay,

[00:59:33.800]so it’s not going that far,

[00:59:35.970]the extrapolation is not unnecessary,

[00:59:39.350]or it’s not extending, for example, 100 meters,

[00:59:42.469]then you need to collect data.

[00:59:45.797]So sometimes I’ve seen people do hacking,

[00:59:51.080]just adding some control point

[00:59:53.420]based on some kind of information or educated guess

[01:00:00.670]or just some gut feeling that, for example,

[01:00:05.004]I think that that location that the plume

[01:00:09.232]or the concentration is zero.

[01:00:11.160]Then you can do that,

[01:00:14.114]but I don’t think it’s scientifically defensible.

[01:00:18.200]So it is hard to justify those,

[01:00:22.327]other than, for example, if you have real boundaries,

[01:00:25.420]so if you have geological constraints,

[01:00:29.450]so the unit is changing and suddenly you think

[01:00:32.963]that from that point,

[01:00:37.537]the plume is not going to travel into that formation

[01:00:41.430]because it really consist of fine material,

[01:00:45.050]the conductivity is 10 or 100 orders of magnitude smaller.

[01:00:49.870]So then you can do those kind of things.

[01:00:53.120]But other than that, it’s just hard to justify

[01:00:56.523]those adding politics, I think,

[01:00:59.110]into science.
<v ->Politics. (laughs)</v>

[01:01:02.098]<v Tim>So got to go back to the data.</v>

[01:01:04.553]You go, Tom.

[01:01:05.892]<v Tom>I think something else too</v>

[01:01:08.600]where hydrogeology can learn from other areas

[01:01:11.100]where geostatistics is applied

[01:01:13.080]is there’s actually a whole lot of,

[01:01:14.453]there’s a really strong toolbox,

[01:01:18.009]a strong field toolbox of methods

[01:01:21.770]to show how robust your estimation is.

[01:01:24.990]You can do swath plots, you can jack knife.

[01:01:30.100]And a lot of these tools are somewhat readily available

[01:01:36.120]and products that are accessible.

[01:01:40.756]And those would demonstrate

[01:01:45.210]and help educate the stakeholders

[01:01:49.560]on the validity of these estimates that they are robust.

[01:01:53.296]I’m not really sure I like the word conservative,

[01:01:56.010]but robust and sound.

[01:01:59.813]And again this is where our field can learn a lot

[01:02:04.070]from what other people have been doing.

[01:02:06.699]<v Tim>Robust is a good word.</v>

[01:02:08.192]And I think that’s a great place to finish up today.

[01:02:12.351]But I do want to thank our experts.

[01:02:15.870]Thank you, Tom.

[01:02:16.703]It’s your evening in Denmark.

[01:02:19.190]Thank you so much for staying up and dialing in.

[01:02:21.280]And, Amir, thank you so much for your time

[01:02:23.899]and for all your comments.
<v ->Thank you.</v>

[01:02:26.780]<v Tim>It’s been great.</v>

[01:02:27.700]And I hope you and the audience have taken something away.

[01:02:32.560]I hope there’s something that’s come from this session

[01:02:35.820]that you’ve learned and you’re going to apply.

[01:02:39.530]And, yeah, it’s been fantastic having you join us today.

[01:02:44.005]This will be available as a recording.

[01:02:46.415]Thank you, guests.

[01:02:47.850]Thank you, experts, Tom, Amir.

[01:02:50.760]And we’ll sign off from here.

[01:02:53.883]<v Amir>Thank you so much.</v>

[01:02:55.632]<v ->Bye.</v>
<v ->Bye.</v>

[01:02:57.340]<v Tom>Thank you everybody for attending.</v>