Comparison

Big River Watch vs Mentarri

Price, ratings, monetisation and update history for both apps, side by side โ€” with what reviewers say about each.

Head to head
About

Big River Watch

Participate in citizen science by observing your local river and reporting on wildlife, water quality, and pollution. Your submissions contribute to a valuable dataset supporting river restoration efforts across the UK and Ireland. The app includes identification guides for wildlife and pollution.

Highlights
  • Citizen science river surveys
  • Record wildlife and pollution
  • Upload river photographs
  • Wildlife and pollution ID guides
  • Offline survey submission
  • Contribute to river restoration data
Features
Read full description

Our rivers face threats from plastic, sewage, nutrient and chemical pollution, which harm wildlife and us. The Big River Watch app is simple citizen science survey that anyone can take part in across the UK and Ireland, that aims to help support river restoration. All you need to do is spend a little time watching your local river and answering the questions in the app. From wildlife and water colour to plastics and pollution, Big River Watch app allows you to record your valuable observations and to upload a photograph of your local river. The app also contains handy wildlife and pollution ID guides. All of the surveys submitted will form a large data set that helps us understand what, and where, some of the problems in our rivers lie. This widespread and up-to-date information is key to support measures taken to improve our rivers. You can complete the survey at any time throughout the year, and you can do more than one survey. Surveys can be completed whilst out and then submitted at a later time if there is not sufficient mobile signal at your survey location. You should not enter the river or put yourself in a dangerous position to complete this survey. The Big River Watch is coordinated by The Rivers Trust and supported by partners and funding from: CIWEM and The Rivers Trust Foundation, for Water Research (FWR) legacy fund and Catchment Systems Thinking Cooperative (CaSTCo) project from the Ofwat Innovation fund.

About

Mentarri

Features
Read full description

Upgrade your human operating system with personalised, practical, contextualised learning. Access to interactive live learning events in all time zones. Mentarri includes hundreds of interactive masterclasses and immersive workshops on topics ranging from Delegation to Design Thinking. All are delivered by our world-class faculty of business school leaders, BBC presenters and entrepreneurs. Relevant, personalised resources & performance support readily accessible to all in the flow of work. Mentarri makes our award-winning multimedia resources accessible in neurodivergent-friendly formats, and in any language. No need to spend ages browsing vast content libraries. Employees get concise, relevant, trustworthy answers and practical recommendations for practising and improving their skills fast. 24/7 access to coaching. Employees can access on-demand coaching and role-plays to practise new skills in a safe way, with instant feedback and advice. Facilitated peer coaching sessions also provide access to supportive learning networks where learners can reflect on their developing skills and share best practice.

Screenshots

Big River Watch4 screens
Mentarri4 screens

Verdict

The call

The clearest difference is update cadence: Mentarri at every 6 weeks against Big River Watch's every 4 months. On price, ads, in-app purchases and device support there is nothing between them.

Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS

CostPrice ยท In-app purchases ยท Ads ยท Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Big River Watch ships an update every 4 months, Mentarri every 6 weeks. The most recent releases landed on November 3, 2026 and November 8, 2026 respectively.

Scorecard1 real difference ยท 7 level
Big River Watch versus Mentarri: the parameters behind the verdict, then further details
ParameterBig River WatchMentarri
PriceFreeFree
Positive reviews100.0% of reviewsโ€”
Update frequencyEvery 4 monthsEvery 6 weeks โ€” better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeโ€”
DevicesiPhone, iPodiPhone, iPad, iPod โ€” better
Requires iOS14.013.0 โ€” better
Further details โ€” not scored
Size32 MB111 MB
Age rating4+17+
DeveloperThe Rivers Trust (UK)Mindset AI LTD

In-app purchases

None

Big River Watch

No in-app purchases

None

Mentarri

No in-app purchases

Questions

Is Big River Watch free?
Big River Watch is free to download, with no in-app purchases.
Is Mentarri free?
Mentarri is free to download, with no in-app purchases.
Do Big River Watch or Mentarri have ads?
Neither Big River Watch nor Mentarri shows ads.
Which is updated more often, Big River Watch or Mentarri?
Big River Watch ships an update every 4 months, and Mentarri every 6 weeks. Most recently, Big River Watch was updated on November 3, 2026 and Mentarri on November 8, 2026.

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